Odin.
Serpent
While serpent is the boring choice, he's obviously great on defense and is also exceptional on offense (just not BG) with good utility.
I have a similar debate (trying to decide between R4’ing Serpent or Medusa), but I think Serpent is the right call for you here. I think there are more options now to take him down as a defender but he’s still one of the best. And he’s an enormously underrated attacker with a lot of utility.
serp or knull