Like many champions a portion of his kit requires another champion for synergy. 

That said, the A2 benefits from no HP burn from a raw damage perspective. (and will be preferable if used in arena, IMO.)

It may shock and delight you to learn you can use other champs on *teams*. Some of them have complimentary skills that benefit other champs.

As it happens though, you generally *don't* want burn with Magnarr, his a2 gets a second hit, effectively double damage, but only if the targets do NOT have burn.

He's worth way more as one of the hardest hitting epic nukers in the game than having a resistable rng stun as a halfassed cc.

Seconding what others have said, Magnarr is best WITHOUT HP burn. But yes, a lot of champs do have that where they'll benefit from a debuff or buff that they themselves can't cast

Thanks for the insights. Actually, I was trying to build a champion with HP Burn to defeat floor 40 of Doom Tower. I guess I'll keep looking.