It's the mount of Megan Cyndewin , queen of the elves (Latari) forces in RuneWars. But they don't seem to have a name for it anywhere in the lore that I can find. All other such characters name not only the creature, but even the personal name for it, but on this one...nothing. Maybe some other obscure lore somewhere does?
https://www.scabard.com/pbs/campaign/235523/character/317875
I've called it a "Mooseboar" for now...but I'm sure there's something for it somewhere.