Ok...the Wild Soul Barbarian...
WTAF??? What is this? This makes absolutely no sense to me. Granting allies an expended spell slot? Uh...no, don't like. It seems like they don't really have any clue as to what to do with this particular path.
It makes sense to me so I will try to describe how I imagine it works.
First, the flavor text for the class: "The realm of the Feywild abounds with beauty, unpredictable emotion, and
rampant magic. A barbarian
exposed to this realm feels emotions powerfully and
magic saturates their body. "
So imagine wild fey magic is like comic-book type cosmic rays.
Like the Fantastic Four, you went someplace otherworldly and absorbed cosmic rays (or in this case "magic") which infused your body and granted you special abilities sourced to those cosmic rays ("magic"). You have a connection to other creatures and objects who manipulate cosmic rays ("magic") too. But unlike them, you don't have much control over it. It's kinda random for you, and wild.
So you have this excess wild power coursing through your veins, and your pal who also uses this sort of power (in a different much more controlled way, but it's the same stuff ultimately) loses some of their power (by expending a spell slot). It's like they have access to a pool of this similar power, but they just poured a glass of that power out of the pool.
But you, you have excess power. It's literally running through your body. It even makes you glow with that power sometimes (when you are near magic items, which are infused with that power and you sense them).
So you pour some of your power back into your pal who just emptied some of their power.
But it hurts you to do this - because that power was literally part of your body, and you just moved some of it to your pal. So you take some damage as you do this. But they now have their pool of power re-filled and can use it like they normally would use it now.
