What it does
Mantle of Inspiration isn't actually a keyword—it's a specific blue Aura from Battlebond. When it enters, you put a +1/+1 counter on each creature you control, then attach the Aura to one of those creatures. That enchanted creature gains haste. If it ever leaves the battlefield, you sacrifice the attached creature.
The nuance people miss: the counters land on every creature you control at the moment of resolution, not just the one being enchanted. So you want a wide board before casting it. Also, the "sacrifice when it leaves" clause means losing the Aura costs you a creature—a real downside you should plan around.
In Commander, it's a niche aggressive tool for go-wide creature decks. It's strongest as a surprise from hand to pump a whole team and give one attacker haste for a sudden, lethal swing.
