Alaiv, Last of a Kind

When Alaiv, Last of a Kind create a legendary 5/5 black avatar token creature named Tenebrian that
has "This token has all keywords that Alaiv, Last
of a Kind has."
Whenever you play a legendary Immortal creature, chose a keyword that has not yet been chosen.
Alaiv, Last of a Kind gains this keyword for as
long as it stays on the battlefield.
"If I am to be the last of the Stariss, then I will deem
myself worthy of such a glorious name."