Spoiler for those who didn't read until ch 291 otherwise summary

I skimmed through the whole manga and a reread a lot (damn that was hard!) so everyone can reread the important scenes themselves! Family relations: In ch. 105 last panel Kuu tells Kyoko she has to act as his son, next chapter a few panels later we get to know his name is Kuon. From here it's obvious. Tsuruga is his son. And his mother's name is Julie/Juliena and she only had 3 months left to live (or maybe that's just what she said to get to see her son again) at the end of chapter 110. In ch. 114 you can't see Julie's face but her appearance and especially the hair seems similar to Sarah's in ch. 290., ch. 291 last panel it's confirmed Sarah is really Tsuruga's mom but I wonder why, there should be no reason for her to use a fake name since noone knows her anyway except the people she has relations with. The name and the eating habits that are like Kuu's really made me think that she can't be the mother but rather a sister because of genetics and the like. Huh... I actually got that wrong I'm dumbfounded!

Actually I thought Rick's girlfriend and Sarah were one and the same person (espacially because Sarah looked sad (in my opinion) when Kyoko mentioned the word 'boyfriend' in chapter 290) but after rereading and ch. 291 I know that's not the case.(I got that wrong): Tsuruga's trauma: ch. 159 page 10 first flashback a woman shouting "murderer" at Kuon(Tsuruga) while holding a dead man in her arms., flashback ch. 161 page 28 Kuon swore he'd never hurt someone again - it's showing his clothes full of blood., at the start of ch. 165 the accident and girlfriend of Rick, the guy who died because of Kuon is shown, then the continuation from page 17, ch. 166 from page 6, Tsuruga's watch is most likely the one Rick wore when he died, it seems like Rick ran after Kuon and the girlfriend ran after Rick then the car crashed into him., the guy with whom the woman was shown at Rick's grave in chapter 285 wasn't at the scene of the accident it seems., ch. 167 page 24 flashback to before the accident, Kuon is younger and talks to Rick, who asks if he pities him, beginning of ch. 169 Kuon and Rick again, the name of Rick's girlfriend is Tina, beginning ch. 189 another flashback of Kuon's fights, after this chapter there aren't any new details shown in any flashbacks about how exactly it came to the accident or any other details about it., ch 285 page 12 Tsuruga says "He's not a relative" concerning who he got the watch from -> Rick. Though it seems I skipped the scene where he changed the watch to one of a different brand as Yashiro said there? why'd he do that? did kyoko gift him one? that's the only reason I can imagine honestly but in that case "He's not a relative" should be "She..." Does someone remember or better know the chapter where this took place?, ch. 285 Tina with a friend? or current boyfriend? at Rick's grave wondering where Kuon went after the accident... So this is all we know until now ch. 291.

Theory: I think 'Prince' Cedric D Bennet (is this One Piece lol) is the little kid that while grinning evily hid behind his mother who slapped young Kuon in one of the flashbacks (didn't note which chapter that was unfortunately. I know it's somewhere in the Heel siblings arc though.) and/or the teenage guy who lead a gang and beat down teenage Kuon saying racist things about his japanese descend. All three of them have wavy hair. And 'uncle tiger'/Mr. D who is Cedric's grandfather said "It'll go smoothly THIS TIME. I'll make sure to protect him... I won't let anybody harm a hair on his head." when he talked with Rory on the phone in ch. 273 page 10. But maybe I'll get this wrong too... ┑(￣Д ￣)┍