It’s so fascinating to see old fandom fanfic tropes built into Manwhas and Mangas. I love love the Sentinel/Guide au so I am more than happy to gobble it up. Some of my favorite fics are based on it!
A/B/O too which started in the Supernatural fandom. It’s amazing to see how complete the world is now with new authors adding to it until it now has its own rules and conventions. I love love the see new twists on it and how some authors play with the gender roles and what it means. It’s a great reflection of how a concept is used to explore our real world heirachys and the patriarchy we live in. Sorry to hijack your comment but it’s rare to see old fanfic tropes talked about here. I feel an ancient person sometimes coming to this site.
It's so wild to me that I used to read Sentinel/Guide fanfiction and to see the Sentinel!verse in BL... it's cool to see it in manhwa but makes me sad that no one knows that Jim and Blair are the original Sentinel (I guess they're calling it 'Esper' now) and Guide. Can't beat the OGs.
I love all BLs with Guides though, makes me feel nostalgic.