The first null manifestation, greeting the player through title messages.
Null Welcome is the earliest recorded null manifestation, announcing itself through title messages such as "HERE I AM" and "Can you see me?" rather than a normal chat line.
Its appearance is also what unlocks three advancements at once, "why are you here?", "null has joined" and "no safe chunk", the first confirmed, documented signs that something in the save file has started to notice the player.