The exceptions which prohibit his appearance are:
Then the Stalker can spawn in almost any player-accessible mission. Players will be marked by killing certain bosses during Assassination missions and being given a Death Mark. If the Tenno marked for assassination has completed The Second Dream quest, they will be confronted with the more powerful, Sentient-enhanced Shadow Stalker instead. The Stalker's signature weapons are the bow Dread, the scythe Hate, and the throwing knives Despair. His arsenal is similar to that of the Tenno, utilizing a primary, secondary, and melee weapon.
The Stalker wears Warframe armor and is able to use ability powers belonging to various other Warframes. The Stalker is an ominous, vengeful figure that infrequently appears during missions, armed with powerful weapons and abilities to hunt down Tenno who have his Death Mark.
