Looking for suggestions for deep romance/love in anime/manga?

Hi, by deep I mean either of these particular scenarios (and in all of them it'd be better if the characters are more mature/older, together and serious and not some weak hormonal teens): 1. The whole anime/manga is not a romance one but revolves around a romance/love story as its core background or starting... show more Hi, by deep I mean either of these particular scenarios (and in all of them it'd be better if the characters are more mature/older, together and serious and not some weak hormonal teens):

1. The whole anime/manga is not a romance one but revolves around a romance/love story as its core background or starting force of the events such as in Vampire Hunter D or Uragiri wa boku that are both action-packed fantasies but there were the romantic feelings of two of the protagonists that started or governed the whole story. It'd be ok even if we're talking an unrequited-love and the love comes from only one person.

2. A scenario in which a more mature man/guy falls for someone but for whatever reason they don't want/can't confess to them and hence continue to watch the subject of their affection from afar. Basically, I want to see the secret yearning in the guy. It's ok and even favorable if the guy is considered a bad one such as in Vampire Hunter D (I know he got the girl eventually but still) or the lusting guy in Paprika. Situations like best friends where the guy is fearful of ruining the friendship and hence keeps his feelings hidden count as well.

3. A story where a guy literally or figuratively traps/kidnaps the subject of his affection and tries to win their heart by force such as what happens in Junjou Romantica where the older guy has basically checkmated the younger one into a consenting relationship with him. How the ending is doesn't matter.

Thanks a ton!
Update: Wow thank you to you both and thank you @Akeath, they fit the descriptions perfectly! :)
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