This is probably mostly an impulse pick for this Man Crush Monday, since I've been watching (and loving!) Hunter x Hunter so much lately, but I'm going with Kurapika!
Kurapika can be a bit cold at first, but once he opens up, he's a total sweetie! He's clever and calculating and almost irritatingly righteous!
But he can also be quite terrifying! I'm constantly terrified that he's going to turn into Sasuke since their stories are so similar! His clan was murdered for their coveted Scarlet Eyes, and he's out for revenge. Kurtas have brown eyes naturally (Kurapika's are more gray because he wears black contacts to conceal his identity), but when under emotional stress, they burn scarlet. In this state, he becomes a specialist, master of all Nen categories (he is usually a Conjurer, his signature being chains), and you do not want to be the object of his wrath!
But he's a great ally to have! I love the way he and Melody are together (I might ship...). She has a calming effect on him when he has an episode and keeps him in check, and he trusts her enough to reveal his secret to her, so I hope she stays in the picture and finds what she's looking for!
So there you have it! So who's your favorite blond man crush!?