Ahaha... I guess you can figure out who these two are.. The letters are a dead giveaway.

Just think of their eye colors.

That's the only hint I'll give. By the way, this may also be a spoiler for one of my works.

Hey, why do you think they chose these names?

How would I know, Achilles?

Well, maybe the Head would've told you..

Nonetheless, I think it suits you just fine. You may seem to be invincible, yet you still have flaws - your Achilles heel.

Yeah. And do you know who that is? You.

You make me vulnerable.