Yuri goes on to confront the architect... and it's nobody. Just an NPC, programmed to do this if things went wrong.
And what went wrong? Love.
The initial author of the Angel Player system had fallen in love with someone who passed on.
As shadows flow around her even in the fantasy world, Otonashi reaches out for her. The last fighters have followed her underground, and they're pulling her back.
If she loses her memories and is reborn with a new personality, how is it still her?
She only gets one life, and it was awful. This is why she fights against God.
Many people choose to move on, leaving only a handful to fight the shadows.
Yuri is engulfed, and finds herself in a classroom, in a classic anime scene. But she doesn't play along and rejects the fantasy.
It stands to reason that they used a similar method to how Tachibana built her powers. Yuri investigates the computer lab.
It turns out someone has been stealing computers. And there's a suspicious underground passageway leading from the lab to the ruins of the Guild.
Yuri has basically never been fooled. She calls out Otonashi to explain his theory to the rest of Battlefront, then lets everyone make their own decision.
Meanwhile, she investigates. Whoever is controlling the shadow monsters has reprogrammed the NPCs.
Naoi as figured out what's going on, and joins Otonashi and Hinata in their quest.
But something goes wrong.
NPCs are being converted into shadow monsters. If they catch and devour you, you become an NPC with no soul.
This new threat forces a reckoning.
But really, what Yui wants is to feel like she's not a burden. Like someone wants to be with her, instead of being stuck with her. Someone to love her and marry her.
Hinata steps in, weaving a tale of how they could have met and fallen in love while alive.
Yui vanishes.
Otonashi chooses Yui, the band's replacement singer, as his first target. She's already the band leader, so she must be close, right?
Haha no.
Yuri was paralysed in life so she's for a bunch of physical activities on her bucket list: Soccer! Baseball! Pro Wrestling!
(I elided Yuri's horror story, which was told earlier.
Invading robber/murderers killed her younger siblings in front of her to incentivise her to reveal her parents' valuables. She didn't know where they were. The authorities arrived only after her siblings were all dead.)
Tachibana turns them in for manipulating her exams. They chalk this up to her losing against her angry selves.
But she's really acting under Otonashi's direction, to arrange a resolution for people.
But can he even do anything for Yuri?
Like everyone else, she's an idiot. Giving them a proper high school experience won't solve their issues.
But with Otonashi's help, they might be able to do it together.
The first step is to reestablish the status quo. Without an enemy to fight, Battlefront is directionless.
Tachibana agrees: this is what she's been pushing for.
This school is full of people who were unable to enjoy their youth, and are carrying that weight. She wants to release them.
This is the emotional resolution that he needs. But will he disappear now?
No. Because he wants to share it with everyone.
(They don't say the words Bodhisattva Vow. But it sure quacks like a duck.)
Tachibana awakens, and it is our Tachibana. Otonashi explains his revelation.
He was my injured internally in the crash, and though he organized all the survivors and bandaged their wounds, he did not survive until the rescuers arrived.
The last thing he did was fill out his organ donor card. He couldn't become a Doctor, but he at least saved one life.
Tachibana is in a coma, but when she wakes, who will she be?
Otonashi stays by her all night. When he falls asleep, he dreams of his own death.
He didn't die in the crash, or at least, not immediately.
It was a cave-in, and the passengers were trapped underground for 7 days.
Unfortunately, the clones have kidnapped the real Tachibana.
The team must fight through the clones to get to her.
But when she activates the skill to reabsorb the clones, well...
All the clones have their own will. Will the original still be in charge afterwards?
Tachibana had developed a skill to clone herself, but had failed to put any limit on the clones. She activated it in battle, and the clone of her was made with the will to fight. Then the clone made more clones.
Yuri hacks Tachibana's computer to change the skill to reabsorb.