"He doesn't have power yet he went to the tree to absorb, now the plot says he still have remaining power in his tower that was stolen. Shouldn't he went to his tower in the first place?"
Do you even read what you're saying? Or the comic? Or did you just not understand? Lucas had lost some of his power, the things in his tower aren't things that can help him regenerate the magnitude of magic he needs to help Athanasia. They're just magic books and trinkets that had been ransacked and sapped of any magical power while he was away. He didn't just go to the tree "because why not, let's be stupid for a bit". He went there because it's some sort of very important tree (forgot the exact details) that can help in regenerating his magic so he can help Athy.
"It won't be a treason since he is also royalty. And if he wins anyway, he can reclaim the throne."
Are you dumb or are you dumb? Treason is when ANYONE, royalty or not, tries to kill or overthrow the ruling party who in this case is Claude. If Anastacius (Claude's brother) just barges in and kills Claude he'll be persecuted by the people. Especially since he supposedly would be coming back from the dead which adds a negative connotation on top of KILLING THE KING. Also we're not sure if he's stronger than Claude. Assassinations and straight-up fights are completely different and play by different rules. He might lose in a straight fight or he just doesn't want to take the chance. It's like you're saying he should checkmate in 10 moves when there's a clear path that could lead to checkmate in 4 or less moves. Completely stupid. Also there's the added issue of mentality. Anastacius truly believes he's doing good by taking back the throne. He wants people to like him and hail him as a good ruler. Killing Claude straight up in front of many witnesses aint gonna give him that.
"the fact that he is the most powerful wizard that lived many years, yet he doesn't know is indeed useless. There are only three people in the tea party, if we use a little brain, you would know who is the third party that can cause this. And now the antagonist cast a spell that is contactless, which is really funny, since the first attempt needs physical contact yet they can't still figure it out."
Again wtf is your brain. Do you really think the first person they should suspect is Jeannette? Especially since Athy knows Jeannette is the female lead in the book and thinks she's Claude's family? If you do then lol no. They wouldn't suspect her for many reasons including:
Athy knows Jeannette is truly a good person from reading about her in the book, having stayed with her for a bit when she ran away, frequently hanging out with her and much more.
Claude used to actually dislike Jeannette but now seems to have gotten to a point where he could tolerate her. He wouldn't randomly be like "OMG ITS HER"
Claude and Athy both are more likely to suspect that someone had snuck in and they didn't notice or it's one of the maids.
Either way, though they won't suspect Jeannette at first they almost certainly will in the coming few chapters after analysing other possibilities.
Also just 'cause Lucas is the most powerful known wizard doesn't mean there aren't others that could rival him. He might just not know about them. Plus the latest chapter clearly hinted that Anastacius has assimilated with some being that is boosting his magic power so maybe that makes him as strong as or stronger than Lucas. You speak as if Lucas is OP. He is not. He is not supposed to be because in the end he IS human.
"she is an adult. she can even use teleport and make coins before she can lift a book which is funny. What is the purpose of her knowing what will happen, this means that she also knows who is against them, its not like there are other people they are in contact, lol. It means that she doesn't think or use her brain, that is why they can't figure it out. There is such a thing called brainstorming."
You're right. She is an adult. Or rather she was. Right now she's a child with the memories of an adult. We don't know how her physical body and memories of her adult self impact her thinking. Maybe she regressed a bit mentally for all we know. It did seem like this happened in the earlier chapters a bit but not too much. Also she only knew about Jeannette getting acknowledged as princess and getting engaged to that dude who's name I forgot. She didn't know about much after that because the book ended soon after. There was nothing about Claude's brother trying to assassinate him. What is she supposed to do? Predict the future? Call upon non-existent dark forces to see if the author of the original novels had written anything else further about the events occurring? Geez.
Your "brainstorming" must be interesting if in their situation you'd accurately come up with the truth of the events. Which is: Claude's death brother was apparently not dead and has been in hiding for over 10 years and is now trying to assassinate Claude through his own weird test-tube baby of a daughter who doesn't know she's his daughter and think's she's Claude's daughter instead. Yeah. Totally obvious. I could totally guess that with a little brainstorming.
"there is something called plot holes. If there are many things contradicting, then it means that the plot is like a spaghetti."
Spaghetti doesn't have holes dipshit. Swiss cheese does though and I imagine that's what your brain looks like with your massive superiority complex trying to plug those holes.