In Order to ChangeDue to his fierce loyalty to Van, Luke blindly follows his orders without informing the rest of the party what he is doing. Luke unintentionally blows up Akzeriuth and kills thousands of people. He almost kills the party as well, but Tear's fonic hymn manages to save them all. As if that blow wasn't enough, he also finds out he isn't really Luke fon Fabre, but rather a replica of the real Luke who is now known as Asch the Bloody. Once safely on the Tartarus, Luke tries to explain what happened to everyone and refuses to take responsibility for his actions. No one listens to his whining because he is only blaming everyone but himself. Everyone but Mieu leaves him alone in the room and he begins to cry out of frustration and confusion. The party then reaches Yulia City. Luke stands sullenly by the entrance while looking at his feet. Tear stops, sighs and turns to ask him if he was coming, too. He informs her he doesn't want to go because everyone hates him now. Asch, who tries to kill Luke on the spot, interrupts their conversation. After losing the fight, Luke loses consciousness and discovers he can now see everything through Asch's eyes. Everyone except for Tear and Mieu returns to the Outer Lands with Asch and Luke realizes what a fool he has been to think they were all his friends after how terrible he treated them all.
Eventually Luke's consciousness returns back to his own body. He finds himself in a bed and notices Tear in a nearby garden of flowers. After going to talk with her, they discuss the gravity of what he has done and how everyone has left him. He sincerely tells her that he wants to change himself for the better, but isn't confident he can do it on his own. Luke wants Tear to watch over him during his journey to change himself and make up for what he did. If he could die and bring everyone who died in the accident back, he would. Tear doesn't take his words to heart, though, and simply tells him that he hasn't changed at all if he can talk about dying so easily. She does, however, promise to watch over him, but warns him not to take her for granted because she could leave him at any time. Luke seems to feel better knowing Tear will stay with him and asserts he wants to start with what he can do. Tear may have to explain things to him along the way, but there wouldn't be anymore excuses. His lack of knowledge would no longer prevent him from having to take responsibility for his actions. Suddenly, Luke asks if Tear has a knife on her. She hands him one and is shocked to see him cut his hair. Luke wants his new hairstyle to symbolize his desire to change and be a better person. Luke lets the lock of hair go and it blows away in the breeze. Luke and Tear then begin the next chapter of their relationship.
Though I wouldn't go as far to say that Tear stayed in the Qliphoth because of Luke, she did still take care of him while he was unconscious. She even let him rest in her own bed (a fact that embarrasses Luke when he realizes it was hers)! Tear's responsibility to look after Luke ended a long time ago, so why did she feel the need to care for him? If she really didn't care about him at all, she most likely wouldn't have done that. Tear is definitely a kind person. Arguably though, she could have found somewhere else in the city for Luke to stay rather than taking it upon herself to care for him. Personally, I think she felt a little responsible for not watching him better and letting Van take advantage of him when she knew he was up to something. Further, she agrees to watch over Luke's journey to become a better person. Every other person he knew left him behind because they were disgusted, disappointed and in disbelief over his behavior. Tear, however, didn't leave him behind. Despite having no reason to return to the Outer Lands, she ventures back out because of her promise to him.
I think for Luke to ask Tear to watch over him displays how much his feelings towards her have changed. At this point, he's realized his mistrust in her was unfounded and now sees how much he does believe in her and trust her opinion. It must have taken a lot for Luke to ask her to stay with him in the context of everyone else, even Guy, leaving him behind. Therefore, I would argue he values her guidance very much because he took that risk to ask. Luke also probably realized how much of their relationship he took for granted in the past. As for Tear, I think she is a little wary. She is likely pleased that Luke is starting to head in the right direction by realizing his wrongdoings and wanting to atone for them. Tear clearly doesn't like when Luke goes on about how he shouldn't be alive because of the bad things he has done; she always tells him to stop talking like that. Why? I believe it's because she is starting to care for him. Luke and Tear still get into occasional squabbles, but they are not as pointless as they were in the past. Their promise to each other becomes the foundation of their soon to be very strong relationship.