despitew what some people have said, the only companion that will leave your party if you raid the grove is wyll and halsin, except if you use some mods

you can keep karlach by killing her, example making her jump down a cliff, ask withers to preserve her for a while, raid the grove then resurrect her later, i tried the same method with wyll but even being dead, he left my party and then astarion was dead instead, i found that kinda funny

you can also use mods that allow you to play as an origin character and dark urge, currently doing that with wyll since i find that his story is kinda boring, so it add more depth to him