Meanwhile at Raiden/Redgrave/Sparda's Residence

Seeing of two couple are currently resting in their bed, feeling their bodies are tired and unable to move in command after having "fun" last night. 

Much to the husband's annoyance. When the sun rise past through their curtains landed on the face. Making him groan in annoyance and slowly waking up from his slumber, slowly sit up his bed.

Revealing it's none other (Y/N) Sparda, the Son of Legendary Demon Hunters Dante and grandson of Hero of Humanity Legendary Dark Knight Sparda. The Hero of Destiny and All the Worlds.

(Y/N): Damn.... I hate mornings... *mumble in annoyance and rub his eyes*

Mei: *giggle* Still bring up the bad past? 

(Y/N): Mei... *soft expression and face his wife next to him*

(Pretend she cover in bedsheet with no glasses and her clothes only cover with bedsheet)

.

.

.

.

.

.

.

(Perv....) 

Revealing it's none other is his wife Mei Raiden, one of the Heroes alongside with (Y/N) and their friends. Not only saving the worlds from the Honkais but Demons and Angels including as well. 

Mei: Hi. *Smiles greeted him*

(Y/N): Hey. *Smiles back and light kiss* Sorry, I disturb you. *Apologize*

Mei: It fine. *Assure him* I still can't help you used to be cute and now you turning into handsome when you remove your mask. *bit of teasing* 

(Y/N): What? I not cute. Don't say that.... I'm just your badass demon hunters more badass than my damn old man... *protest with red tint of cheek in embarrassed* 

Mei: *giggle* I know.... That's why I love you, but... Are you sure? It been a while you visit her... *frown in worried* 

(Y/N):..... *remain in silence* 

Mei: *frown and realization* I'm sorry.... It almost Christmas.... But, she do... *cut*

(Y/N): I know.... She doesn't want to see me sad and suffering.... But I am not alone... I have you, Bronya, Seele, Theresa, Himeko, Rita, Bianka, Kokoro, Isabel, dad and.... Even Glenn... *quick bitter disgust reaction*

Mei: *Smiles in giggle* (Y/N), don't be mean. He one of your adoptive uncle. He may be foolish and childish teacher. He taught you well. *defend Glenn with kind smile and sit up her bed* 

(Y/N): *big sigh* You right.... I admit that I couldn't survive or help by him, whenever I get in trouble by Demons hunt me down.... But, he always have responsibility to take charge in action... He does care for me and other guys. *Smiles sweetly at his wife* 

Mei: *giggle* Told you.

(Y/N): But, today is her birthday. How about we do another round. *knowing smirk*

Mei: N-N-Now?! We can't! We have to get away to vi- *tried to protest only let out yelp when (Y/N) pushes her laying down on bed*

Both lovers kissing passionately, Mei have no strength to fight back. Slowly accepting kiss back, feeling her body begins to heat before they pull their heads out leaving their strings of salvia connected their lips.

Mei: Mou.... You so mean, (Y/N). *pouted*

(Y/N): Well.... I just want to do it with you~ *smirk with flirt*

Mei: *big sigh* I guessing you becoming bit like your father... Well, whatever. *form smile* Let do it. 

Both husband and wife went giddy and continue their passionately make out. Before they could do anything their moment have been interrupted by someone calling him on phone.

(Y/N): *big sigh* Wonder who calling me. *irritated tone*

Mei: Well, guess you need to answer it... *small smile*

(Y/N): Yeah, yeah, yeah, yeah. *answer his phone* Redgrave spe-

[Adam: (Y/N)! You gotta help me! *panicked tone*]

(Y/N): Oh, it just you deadweight. *deadpanned* 

[Adam: What you mean, it just me?! *irritated tone turn panic* Alright, listen! I need you help!]

(Y/N): It is about my damn troll uncle? You literally have no idea how much I suffer deal with his damn bullshit and craziness full of weirdness and shit. You the one wanted me to introduce of the troll. So deal with it.... *blunt tone* 

[Adam: You don't understand! You have no idea, how insane with that man?! Me and Lyle can't stand him! You gotta he- *tried to help*

[???:... 

https://youtu.be/KmP75i_X7eo

[???: A-D-A-M.... Is that (Y/N)'s voice? *familiar troll grin*}

{Adam:

https://youtu.be/4HkZtwvUCLo

(Y/N): Yeah.... I'm not doing with this bullshit. Good luck kid. *tired tone* 

Adam desperate begged (Y/N) tried not to hang up on him and help him. But too late. He already hang up.

Mei: (Y/N), was that necessary? *frown in disappointed*

(Y/N): What? You mean the deadweight? You all know he such a nuisance to me, Mei. *blunt tone* 

Mei: (Y/N).... *showing her dark menacing intimidating* Adam is my student and part of my squad as well, I don't like him treated him unfairly.... But... *went softly* Adam really look up to you. All the boys of St Freya Academy look up to you as well. You the new Generation of Knights gave the boys opportunity. *remind him* 

(Y/N): *big sigh* You right.... *face his wife* But, that kid Adam can be pain in the ass sometime, but he really good kid. *Smiles* 

Mei: *giggles and lean in closer* I knew you have soft for him. *kiss* 

While the lovers having their moments, suddenly their moments rudely disturb when someone barge enter through the room.

Eva: Is mommy and daddy playing? I wanna play too! *barge in flying in midair launch at bed*

(Y/N)/Mei: Eva, don- *tried to stop with their face blushed embarrassed knowing they not wearing their clothes and Mei cover her chest with blanket* 

They tried to stop their daughter, only Eva landed on her parents causing them fall down by her push. Making the entire family can't help let out smiling and laughing of their antics. 

Luckily they able to cover their naked bodies from their daughter's eyes in order to protect her innocent mind. 

Timeskipped brought you by chibi (Y/N) and Kiana form love hearts on their hands!

And so after Eva being told to leave their room, the parents able to put on their clothes. Mei ready to leave take Eva to visit her adoptive sister. And (Y/N) going to visit... Old friend for long time. 

After long miles of direction, (Y/N) finally arrive where he wanted to be. The Old Cabin once belong to Kiana.

(Y/N): Hey, Kiana.... It's been a long time... *Smiles fondly*

He walk toward at the cabin, not before he pulls out the box from lifted the bike's seat. (Y/N) manage to open the door and enter the cabin looks clean.

(Y/N): Sorry, I was late.... Busy you know. Usual.... Being as demon hunters kept me busy who would tried to disturb and ruin their days and peace.... But at least I managed to be here.... *chuckle with sad smile* But.... I know I didn't miss your day today.... *sit down and place box* Happy Birthday....

(Y/N):.... You know.... Remember like the first time we met, you didn't like me because I "stole" Mei from you. *chuckle at memory* At each time you always kept arguing due I having logical tactic and you have none... As the time grew... We getting closer... Closer... Closer become friends. Comrades. Partners. And Lovers... *forming tears spread* Like Kaslanas destined to be with their devils...  Proven they have hearts and soul as well... 

Flashbacked

Showing the fragment of flashback, Kiana scowl and shouted dislike toward at (Y/N) being close when they were young in between with Mei.

Next Flashback

(Y/N) save her carrying her in bridal style, making the Luna Cat tuna blushed in madly. Save by the Dark Crimson Knight from her near-end from Mei has become as Herrscher. 

Next Flashback

Kiana shouting in nonsense she complaining to do some homework prefer to do some video games. Made the young Sparda to be grew annoyed and irritated before flick her forehead being childish.

Next Flashback

Showing (Y/N) in shirtless determine to save Kiana when she first touch the Herrscher's core causing her become Herrscher. During their missions to save Professor Magi and his granddaughter. 

Next Flashback 

Kiana hugging (Y/N) in relief he is alive, (Y/N) become surprised and slowly accepting to hug back. He let his first words to him.

Next Flashback

Kiana let out tears and held back by Himeko and Theresa tried to reach for (Y/N). He sacrifice himself to give the other some time to escape. 

Final Flashback

And showing the memory of the Flashback, seeing of (Y/N) outside in the park area. (Y/N) can't help staring at the snow. Suddenly, there is hands covering his eyes.

???: Guess who it is? 

(Y/N): If it the damn troll, I would like to punch you in the fucking sun. No wait, it defiantly you Tuna. *blunt and deadpanned tone* 

Kiana: Mou! Still calling me that?! *pouted upset* 

(Y/N): Yeah, could you be more apparent? Also, where the hell have you been? I have been waiting for an hours. *blunt tone*

Kiana: We-We-Well.... *tried to find excuse but escape point finger at him* Where were you?! Why you just standing here like a loner! *rant* 

(Y/N): Nice try. *roll eyes* But, I defiantly knew you would tried to get some snacks, you gluttony tuna. *deadpanned* 

Kiana: Gack! *got stab by imaginary arrow*

Making Kiana comically depressed on the floor with aura surrounding her. 

Kiana: No way.... My boyfriend just being mean to me~ *crocodile tears*

(Y/N): I'm just saying the fact. *blunt tone* Also... Here... *offering some cup of milk tea* 

Kiana: Milk tea? For me? *surprised tone and take a sip* Umai! This really made my body feel warming up. Nothing can beat hot milk in winters. *smiles gleeful* 

(Y/N): *chuckles and smiles* Kiana... Next time if you get lost or feel hunger for snacks.... Stay with me.... I don't want you to get lost because I care for you. *Softly stare her eyes*

Kiana: (Y/N).... *can't help blush and forms tears not before lunge hug him* 

(Y/N): Whoa! Kiana! *nearly lose his balance* 

Kiana: (Y/N)! I love yo- Ah-ah-ah... Ahcoo! *Sneezes*

(Y/N): *luckily miss* Almost got your sneeze. Also... *remove Kiana's off him and place his scarf on her* Here.... This could warm you up.... 

Kiana: Wait, (Y/N)? *surprise his action* Aren't you... *feel concern*

(Y/N): It's fine, I'm Quarter Human, remember? No temperature could effect me. *reminded her* Also... I knew this would happened you didn't bring a scarf on a day of this cold. *shook his head* 

Kiana: Don't worry about me, (Y/N)! I'm okay! I am really tough to catch a cold. *Assure him* 

(Y/N): *chuckle her antic* Whatever you say. But I can tell your nose tell me about it. We go home later, but fast.... *face at snowman* Wanna finish the snowmen?

Kiana: Yes, please! *smiles graceful* 

And so both lovers continue proceed building Snowmen for Kiana's birthday. However... Kiana feel frown and concern, making (Y/N) concern for her.

(Y/N): Kiana, are you okay? *Question her in worried*

Kiana: (Y/N).... You are going sacrifice yourself? *face him in worriedly*

(Y/N): What?! Kiana, what you say- *cut*

Kiana: (Y/N).... I know no one would able success in killing you due you have healing factors. I thought no one would finally kill you... But instead I was.... *tears forming* 

(Y/N): Kiana... *tried to comfort her* 

Kiana: I don't want you dies! Everytime your past selves kept suffering and always meet their fates! Are you planning to sacrifice yourself?! *demanded with tears*

(Y/N):..... Yes. *confess* I am.... When I talk with Kisei and Sora.... They both risked their lives and using the ultimate powers knowing it would kill them... 

Kiana: But why?! It not so fair, why can't they have happy ending?! 

(Y/N): As much I don't believe in Fates.... It their fates... They all know they have to end this so their love one can live up in better lives without pain and suffering... I have to di... *cut*

Before he could finish, suddenly he was not expected by Kiana throw a harsh slap on him.

(Y/N): Ki-Kiana... *surprised her action*

Kiana: (Y/N)! You baka! Why planning to throw your life away for nothing! Are you an idiot?! *scolding angrily at him*

(Y/N): Kiana, I have to... It for... *cut*

Kiana: It's not about some humanity! It not about the world either as well! It about us! We won't live without you to see the future shrine brighter! *scolding him*

(Y/N): Kiana.... *felt touch*

Kiana: (Y/N).... You not only change my own Destiny. But Mei-Senpai, Bronya, Kokoro, Himeko-sensei, Aunt Theresa, the girls and everyone else's own destiny. You always tell us... We defies Fate what coming to us, but we make our own destiny. Destiny is a great believer to make our own future and by our side not only protecting mankind but to protect our love one. *in wise and compassion*

(Y/N): *Surprised she use his own words against him* 

Kiana: (Y/N).... Promise me you won't die and sacrifice your life for nothing... Kallen already suffer she lost Kisei for long time ago.... Our hearts won't take it.... *crying*

(Y/N): Kiana.... *softly and realize his action and plan effect her and pulls her hug* I'm sorry.... I promise I won't throw away my life for nothing.... I promise... I will spend the time with you... *promise her* 

Kiana: (Y/N).... *Sob on his shoulder*

Both lover pull out their hugs. Felt their eyes staring can't help admiring how beautiful they are. Feeling their hearts skip a beat, before slowly close their lips meet.

Flashback ended

(Y/N): Please, come back to us... Kiana... *crying*

He lean down his face against his arm on the table, let out sobbing. Unaware there is a beautiful white shine appear out of nowhere close next to (Y/N). 

She place her hand on his hair to rub.

???: I will.... I will my love.... I will always with you... 

Making (Y/N) snap his eyes open, causing him to sit up after hearing the familiar voices.

(Y/N): Kiana?! Where are you! *shouted desperately* 

Eva: Papa! *shouted outdoor*

Kokoro: (Y/N) Onii san! *shouted at outdoor* 

Mei: (Y/N)! *Shouted* 

Making (Y/N) let out a small flinch, he turn facing at the door hearing the voice of his wife, daughter and sister in law. Not before he glance at the table, noticing the cake went missing.

He doesn't look shock or surprised, but knowing how it is. He can't help form the smiles.

(Y/N): Kiana.... *Smiles*

He have a feeling about Kiana is doing well and okay. She always watching her friends including the man she love. (Y/N) walk up join with his family, and Kokoro jump in her father's arms. 

At Moon

Meanwhile on the moon. Seeing a familiar moonlight Kitten on the moon, can't help staring in admiring of the Earth. 

Goddess: Soon... One day, we will be reunited again my love. 

Little girl: Mama! *rushes to her* 

Goddess: *scoop up her daughter* Cecilia. 

Cecilia: Mama, are you seeing Papa? What papa doing? *ask in curious*

Goddess: He.... *Smile fondly* Just being your Demon Hunter pasting through.... Being a Hero. Want to say hi to Papa? *ask her daughter* 

Cecilia: Okay! 

Cecilia: Hey papa! I want to meet you soon! *Smiles gleeful wave at Earth*

Inner Goddess: One day.... Our daughter will meet you... (Y/N). 

End of Birthday Mission