Hey Vls, Hail/Abstane here
I been playing level 8/9 for many seasons now and in your situation I would sell that Grimm and buy something like Dovabear.
The main concern in Grimm is the lack of mana regen. If your not with a Warrior or Mage who was nice enough to put the mana upgrade on Lifegiver you will find yourself either constantly out of mana or running back to a Team Base to grab the mana boost.
In terms of Dovabear, its basic stats are much better (more health, damage and mana) than Grimm's and even arcane pets such as Hammerjaw and Glacian and it comes with that nice +100 mana and 8 mana gen which is super handy for Low level rogues such as ourselves.
In the end, the decision is always up to you however I suggest taking Dovabear over Grimm due to just being better in pvp.
See yah round in pvp