Guessing Senna's kit based on her VO
Passive
"Death is drawn to life" "Be free" "Out of the storm" "You are mourned" "Let go" "Rest now" "Pain doesn't own you" "It's not your fault" "I can bear it"
I'm guessing this is an interaction with already-dead allies.
Maybe she can channel on their corpses to make them respawn?
E
(Raspy voice) "Death remembers" "One last breath" "Shadows catch the fallen" "My enemies, myself" "Together"
This is most likely her "turning into a screaming cloud" that she mentions when talking to Lucian. Functionally, it's probably something along the lines of Moria's fade. Go untargetable and get a speed boost. Might deal damage to people you pass through.
R
"No Shadow without Light" "No Death without life" "I've got you"
Likely to be the ability we saw Fire off a shot. Allies struck are healed and briefly shielded from harm. Enemies struck are damaged and knocked away.