Wow, that's a screwy mana cost.

Protection from (screwy) is more of a blue thing than other colours; but flavour can justify most anything if you try hard enough.

A 2/3 first striker is pretty powerful; but the extra cost making it gold in three colours isn't really justified by vigilance alone. I'm tempted to suggest that it just flat out gets "~ has protection from non-elf creatures" without needing an activation cost. (And I like playing with funky activation costs)

But that's a somewhat terrifying possibility as an EDH general.

Dunno. It's a hard ability to cost; it's kinda like invulnerability and kinda like unblockable but also kinda not. Maybe it does need to cost this much.

I know that this cards seems hard to deal with but note that it only gains protection from creatures you can still target the crap out of it with spells to deal with it.