Ikazuki attacking Jade, cutting her bangs and scarring her forehead.
Not to mention the Jerkass cursing her and denying her access to any of her tribe other than Left and Right.
The vision Jade has of Kagehime, the inhuman girl who created the first Shadowkhan from her shadow to help her get food is pretty sad in a number of respects.
The scene where Lungtortures Jade, driving her to the brink of insanity and nearly killing her is so bad, at least one reviewer PRAISED Lung being Killed Off for Real by Right, calling it justice.
Jade's mental trauma from the above is getting worse and worse...
What we've seen of Blankman's past: His father lost the family fortune and used what was left to secure his son's education and future... and as soon as he left the house for the last time, shot himself.
It gets worse, Blankman apparently became a Death Seeker in his later years, hoping that Death Equals Redemption for his previous actions under the cult that trained him, until he found a new purpose in life.
The Reveal that Jade was nearly aborted, and only exists because her mother had second thoughts as they were literally right outside the door of the clinic. Jade doesn't take it well.
Jade forcefully transforming Viper into Hebi.
The reactions of Jackie and the others when they find out that Viper was turned into Hebi.
Scruffy briefly appears in the seventh interlude and shown to have been depressed ever since he betrayed Jade, even if it was justified.
The sages saying their goodbyes before going to make a Last Stand.
Ozeki being Killed Mid-Sentence by Tarakudo for trying to help Jade. Jade even feels that something is fundamentally wrong about him going out like that.
Jade desperately trying to heal Left. And despite Right's betrayal, she still reaches out to him as he's being sealed.