Hello!
I've been reading up on rogue covenants in shadowlands and seen that most people are have already decided that Necrolord is the best choice. However, I would like to argue that Night Fae is better for assaination rogues particularly.
The Night Fae rogue class ability sepsis applies a dot to the target that at its expiration (10 sec) vanishes the rouge, which is basically what every assassination rogue does in single target anyways. Right now, the opener looks like: garrote, rupture, garrote, vendetta, mutilate, rupture, exanginate...vanish when exsanguinated garrote falls off and re-apply bleeds. When you exsanguinate a 22-23 sec garrote it turns into a perfect 10 sec dot. Therefore, the opener with the night fae ability would look very similar and not use vanish. It would go: garrote, rupture, garrote, vendetta, mutilate, rupture, exsanguinate, sepsis. You would vanish right when your garrote falls off without actually having to use vanish. This is most certainly not "awkward" and if anything is a big quality of life improvement letting us keep vanish as a defensive. I don't really care about how it plays in open world content because generally I am not using my 2 min cds to kill random mobs anyways.
In multi-target situations you could open with 3 garrotes then immediately sepsis and potentially have 6 empowered garrotes out at 1 time.
For me, serrated bone spike seems like a filler ability at best when the rogue is low on energy 1 min into a boss fight. There is no place for it in the opener for sin rouges because in the opener there is no issue with combo-point generation. In the sin rogue opener you are fighting the GCD. The only thing that I see being the deciding factor is if bone spike just does ridiculous damage. If this is the case then blizzard has really failed because sepsis so obviously synergies way more with the current sin rouge build.
If I am missing something then please enlighten me, I don't want to look dumb being the only night fae sin rogue.
Cheers.