Kiki had a twin named Nirisa. Her closest friend besides Hahkin. Nirisa was the golden child of their friend group--near-mastery of the Force and her special ability, which was foresight. Even tho they didn't see eye to eye a lot of things, Kiki felt connected to Nirisa the way nobody else could. Perhaps they didn't need to agree on everything because they were in tune with one another already.
Nirisa makes efforts to be closer to Kiki, spend more time around her. She offers advice more, tells her to calm down more, basically nags Kiki more than usual. It goes on for days. Random calls in the middle of the night. Kiki first tolerates and then ignores and then pushes back on it.
Nirisa dies--is killed right in front of kiki. Kiki realizes that Nirisa had been attempting to say goodbye for four days straight because she'd foreseen her own death.
Kiki can barely cope with the pain, so she pretends her sister hardly existed.