No, it's not the pen. It's the ownership itself. The control.

His sister wanted something and got it, and that's what he wanted to steal from her.
Just like he stole her career from her... Killed her and become a lawyer, cause it's like take her dream alongside her life... The psychical stuffs are just trophies of that achievements, that's why he's so fixated on them, and that's why they're inreplacable.

he did the same with the watch, and all the other stuffs - those were important for somene else, owned by somene else, and that's why he wanted them. because they had it, not him. 
He literally killed someone just to show up later on the funeral and meet his "love"..  because if he want something, he will get it.
This is what the word "shine" means for him. When something is highlighted for him, just like when you point at something to pick up in a video game.

The question is, why those certain things were highlighted, and not the 10000 other stuffs that people own, keychins, cars, whatever... I guess we have some clues already, but it's not really make sense yet... at least not to me.

(Anyway, that funeral scene is a direct reference for a famous game-like "test" for spotting the psychopats. (not a serious test, oc, but a fun one, like a riddle that only the psychos supposed to answer.
In short, a grandma dies, and a lot of people go to her funeral, including her granddaughter.

Next week she kills her little sister. The question: why? The legeds say, nobody knows, cause normal brains can't connect the dots, but a psycho would know instantly she met someone at the funeral that she wanted to see again, so she killed her sister, hoping that certain someone will come to the funeral this time too.)

It's called antisocial personaity disorder.

he wants the woman and the kid is in the way.

nahh, hje's so, so, SO FREAKIN SLOW compared to L...

...Actually, L wouldn't even had bothered with this case. XDXXDXDXDXDXDDDDDD

uhmm... what do you mean...?

Why would they treat him as a mere infant when he's doing all that stuff??

...I read this story. the question is, what you tread to not realize what is he doing at the first place..:? :D

I mean, you just said he didn't tell him directly - how do you not understand why?, BECAUSE HE HAS A BRAIN! He KNOWS it would trigger J, that he would understand what it means, but it's NOT enough to report him to the police or anything, meanwhile it gives a high chance J woould flipped out, ruin his public image even more. make his mental state even  more unstable, which could affect his perofrmance, _and_ on the top of that junmin can do what he did and loved all in his life, hurting people and makes them miserable, like a good old sociopath always do. 

And that's exactly you're just wrong literally in everything, like, you yourself stated what a freakin mastermind he is, I mean, he achived _so many hurtful things_ with one single sentence, and you wanna tell me he's not smart?? wtf?? :D

He ran a fuk*** gang as a teenager, they were running a drug business, and you call him a  single"bully??"

...And I'm not reading..:? :D::D:DDD

And no, nobody said there should be a police investigation, wtf are you talking about, it literally can be done in 2 panels, half of it already done with 2 sentences abot cctv and "we know who did it, we just didn't catch him yet".
Just like nobody said the fight should last longer, that's not what i'm talking about, and you know it pretty well too, why do you want to shift random bs onto me......

ps: no, logic and consistency for characters are NEVER poor writing, seriously, what the he** are you talking about... XD