Very interesting thread and I'd like to add a few myself but under different conditions of the OP:
Code Geass
*I'm not gonna say he's untouchable and he obliterates his enemies, but he's omnipotent, whether his power is used for the right or wrong reasons.
Fate/Stay Night - Unlimited Blade Works
*Untouchable? Maybe not entirely. Able to obliterate his enemy? Possibly. Not bad for a once ordinary human :P
Death Note
*Definitely untouchable and able to obliterate his enemies
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