Shit...

How is Ein risking his ass for him? They are after Ein because he was an undercover cop who killed the son of the mafia boss. Right now he isn't risking his ass for Diesel, he's trying not to rope him into this. Ein made it pretty clear that they are after him out of revenge (he thinks they're his father's man and not Yanek's). Even if Diesel died or disappeared they would still go after Ein.

So, we're gonna pretend in Yanek's mafia family, they don't know about Diesel? Or that he yanked the chain off of Diesel's neck holding on to proof he was involved? The fact that Yanek believed Diesel was a "traitor?" Of course, they won't stop until both are dead. Just because the police don't know about Diesel, doesn't mean the mafia doesn't. And when I say protecting his ass, I mean exactly that. He keeps him as far away from harm as possible. ╮(￣▽￣)╭

They're not Yanek's people, they're his father's men. Ein himself said that he's the target, not Diesel. They want Ein and they will kill Diesel if they find him but Diesel is barely more than a casualty to them. Ein made that pretty clear in chapter 59.
If Diesel was a real target it would be extremely irresponsible of Ein to send him to Siberia with only Minsuk and Bexan. He would basically send him there to get killed. People around Minsuk and Bexan know they're leaving for Siberia. It's extremely easy to track them down and find out that Diesel went with them. And then he's in Russia, with the Eastern European mafia after him without any noteworthy protection other than his own skills. How would that be keeping him as far away from harm as possible?
Ein is the "harm" here. He's the target they are after, which was mentioned numerous times, and Ein tries to protect Diesel by keeping Diesel away from him. According to Ein, Diesel is safe as long as he isn't with him.

I forgot one thing. Yanek's people don't know about the necklace he held when he died. The corpse was found by the police, not the mafia. If the police doesn't know about Diesel being there then the mafia doesn't know either. There were no other mafia members at the scene, we saw no one (other than Odin) at his house when he left. They probably know by now that there was something going on because Diesel and Ein are together in Korea but they shouldn't know what DIesel did when Yanek died.

See, we don't know that. Yanek's dad, Yanek's people, same thing. He is avenging his son. They all belong to the same mafia family. Even if all they know is that Ein and Diesel have a "relationship", that's still enough of a betrayal. Ein has convinced himself they are only after him but I have not seen anything indicating Diesel isn't being looked for. You're going to tell me that the man Yanek was banging and was his personal hitman for quite some time disappears and it is not suspicious? Let's say they don't know he tried to stop Yanek, because he sure didn't harm yanek to save Ein, it is enough that he escaped unscathed and running around with Ein. My whole point is, Ein got stabbed and shot for Diesel, almost lost his life for him. Risked his mission along with his very life for Diesel. I have yet to see anything remotely the same returned to him. I want them together. I am rooting for them but all I have seen is Diesel staying with Ein because of his fear of being left w/o anyone. ╮(￣▽￣)╭

Yeeeeeeessssss

It's not the same thing. There's a huge difference and it was explained why. Yanek wanted to kill Diesel and Ein for betraying him. Yanek's father wants revenge for his son's death. The one who killed him is Ein not Diesel. They will kill Diesel if they have the chance to but he's not the one they're after.
I didn't say Diesel's behavior isn't suspicious, that's why I wrote
"they probably know by now that there was something going on because Diesel and Ein are together in Korea".
And it was proven by the story itself that Diesel is not the target. They were at Pablo's place and they found them because of a picture posted by Pablo. They would've found Diesel by now if they were looking for him. Then there's the fact that Diesel was on his own for months after he disappeared and they didn't bother to search for him or kill him. There was only a single man who was sent after Diesel while Ein's apartment was filled with hitmen. Diesel killed people for Yanek. They knew one guy was no guarantee that he would die. If Diesel is as much of a target as Ein, why did they even attack when they were separated? It would've been easier to kill both of them together. Unless they're only after Ein. Then it's easier to concentrate on the one who has priority.
This and the fact that it was mentioned all the time made it pretty clear that Diesel is not the real target here.
Why would Ein even convince himself that Diesel isn't also a target? If Diesel was also a target they could stay together. And again, it'd be extremely dangerous for Diesel to go to Siberia if he was a target. Ein would put him in great danger if that was the case.

There's one thing we should never forget when discussing something like this: It's too much for the story. It's the same as the "Yanek is still alive" theory. Making Diesel a target but putting them in two different locations means we end up with two different storylines about the same thing. They're going to Siberia. The Eastern European mafia would be after him there. Their entire stay would be about Diesel being chased by the mafia. Bexan and Minsuk's story would be irrelevant again.
Now, if Diesel isn't a target their stay in Siberia could be used to develop Bexan's and Minsuk's relationship and to give Diesel time to think.

"Ein got stabbed and shot for Diesel, almost lost his life for him. Risked his mission along with his very life for Diesel. I have yet to see anything remotely the same returned to him."
You have seen it. You saw it when Diesel returned to Ein and decided to stay with him despite of how dangerous it was. You saw it when Diesel was almost killed in that shop by a guy who was only there because they are after Ein. You saw it when Diesel ran to their apartment trying to save Ein from the hitmen that were there.
That's the entire point of their story right now. At first Ein put himself in more danger than necessary by being with Diesel. Now Diesel is the one who puts himself in danger for being with Ein. They want to be together but they can't.

Unless the police returned that necklace to Yanek's father, because after all the investigations were done, maybe they thought the necklace wasn't part of the evidence.
Ein probably hid the necklace, but if he didn't, Yanek's father knows that Diesel was present in the scene of death, and he knows who Diesel is.

I'm a bit skeptical about Ein saying that Diesel is not a target in ch 59, because he doesn't know how the mafia found him. Ein thinks that informations about his whereabout were leaked by interpol o something like that.
What would he have said if he had known that the mafia had found him because of a online photo of Diesel?

I thought about it but it seems unlikely. Ein covering up but forgetting the necklace is already a reach and the police not considering it to be evidence when he held it in his hand (he obviously ripped it off from someone else) when they found him seems even more unlikely. Plus they would have to give something to his father which isn't obviously from Yanek. And even if all of these things happened just the necklace alone doesn't say much. They'd have to tell him how they found it, too. Otherwise the necklace could've been in his pocket.

He's completely aware that an online photo of Diesel can reveal their location. That's why he told him in chapter 36 to not get photographed. So I guess he wouldn't think differently.

Mmm...your theories seems more valid than mine.

We don't know what happened to the necklace. Yanek purposely yanked the chain off of Diesel. Why would he? This is the mafia, not just some regular neighborhood gang. Yanek was in deep shit, Ein was in deep shit and Diesel was in deep shit because of Yanek. He became a killer for Yanke. If you think for a moment that the mafia and/or police is not looking for Yanek's # 1 killer/lover, you are missing the bigger picture. Yes, he chose to stay with dangerous undercover cop Ein but we can't ignore why he stayed by his side in the first place by his own mouth. "You're all I got now"...Diesel also stayed with Yanek whom was also extremely dangerous for all the wrong reasons. There is a detached go with the flow afraid to be alone aura about Diesel and until the author decides to shed light and expand on his character, I'm stuck with seeing him this way. ╮(￣▽￣)╭ And I like Diesel a lot but I see what I see. He is now going to Siberia w/o Ein. Once again going with the flow. He can choose to stay by Ein's side and face whatever danger together. I can see your points and you make them well but I still believe what I am saying with Diesel. We also know this mafia is big, strong and with deep connections. Ein said so himself talking with that lady.