Cool card, btw. Feels almost like it could be in an 'Un'-set.

Yes, I didn't see this when it was made. It's the obvious companion to Doran, and red is the natural colour for it, I really like it.

I think it may need to be templated slightly differently though, though I'm not quite sure what would be correct. IIRC it works as written, but it may be confusing with a 0/1 creature (I think it would have lethal damage, but survive if it was indestructible). Maybe prevent damage instead, or give +0/+P, even though that's less snazzy than the reverse-Doran effect?

Odd question. Is this really red? I mean, it's effectively adding toughness to your creatures.

That said, I can't imagine it being any other color. Maybe its 'real' cost is ?

I'm sure that it's probably a multicolor-only effect.

I didn't have a flavor in mind for the effect, so I gave it an un-flavor.

I don't recall spending a lot of time pondering the wording. If Doran, the Siege Tower can work, I'm convinced that this can, too.