Forum announcement today that Adventuring Fellows are getting buffed! Soloers rejoice!
Adventuring Fellows are basically pets you can summon to fight alongside you, heal you, make skillchains with you, etc. for a given amount of time, until you kill a given number of mobs, or they die. You summon them with an item with a 20 hour cooldown, but once a week you can do a five-minute quest to get a supplementary summoning item with 5 charges and a CD of only 10 minutes. They take 30% of your XP for the privilege, but level up on their own and gain XP as if they'd killed the target alone.
The current level cap for Fellows is 70; the next update is bumping that to 85, doubling the amount of time they can stay out, and tripling the number of mobs they can kill before they leave. This is huge for Magians stuff, if that weren't obvious, but moreover it basically means in practice that your Fellow is now a permanent fixture while you solo unless you die or warp a lot.