Many people were not Forsaken until they were slain and reanimated. Just look at how many Gilnean refugees, presumably still loyal to Gilneas, were slain in Silverpine and immediately joined the Forsaken. Then look at the Alliance-loyal farmers and laborers in the Plaguelands that underwent the same thing.
Length of time being undead and the kind of person you were before dying are not considerations for joining the Forsaken.
Not sure we know anything like that yet. We barely see her throughout BfA. She’s been in hiding, and we don’t know how she’s dealt with being undead.
Forsaken are almost predominantly Humans, High Elves, and a smattering of Dwarf and Gnome. Undead Nights Elves fought for the Forsaken on Darkshore.
ALL Alliance races, formerly.
Presumably she’s only hiding with the Alliance because she made herself a political enemy of Sylvanas Windrunner, who I don’t think was ever aware that she’d been reanimated. Revealing that she was not only not dead, but now also undead, she posed an even greater threat to Sylvanas’ leadership than before.
The Forsaken are about conquering death and carving out their own place int he world. They’re melancholy because being undead is kind of awful but there are Light-practicing Forsaken. Light-wielding Forsaken have been canon for a long time, and no one ever said they were less Forsaken than other Forsaken. How much Light is too much Light?
Also she’s a Discipline priest in Legion.
In WOW’s cosmology, the realm of undeath is still proximal to void and shadow. Even if she was pulled from the brink via the Holy Light, she’s not truly LIghtforged, and it’s likely she’s carrying some taint of shadow that is inherent to undeath that she will have to balance.
Bolvar isn’t technically undead either. He got lit up by dragon flames that sealed his fate. No one’s questioning whether he’s not enough “suffer well points” to lead the death knights of the Ebon Blade.
After she decided to claim the throne, the first to embrace her were other Forsaken. Even Anduin was caught off guard.