Grover's axes do so much damage at long range, that Grover can potentially have more damage-per-second than Kinessa at a certain point, making him a strong option for dealing with her at a distance.

Grover does not exactly counter Kinessa, but can be very annoying to her by simply throwing axes in her general direction, forcing her to constantly reposition, unable to take proper aim.

Very easy to get a long range two shot kill. Usually in lower ranks the Kinessa will not react quickly, allowing you to get a second throw on.

Buy cauterize, if he tries to heal himself from your shots, he won't be healed enough to stay alive.

Grover can do a lot of damage to your teammates trying to get on point. Consider flanking to Grover's Spawn's side and shooting him. This will make him have to focus on you and not killing your team. May throw off flankers for a bit. STILL DANGEROUS!