While Tsubasa Reservoir Chronicles has its own rich lore, it is made even more enticing by its connection to the series xxxHOLiC. Both series were developed by Clamp and are set in the same multiverse. Characters are shared between the two series, and the interdimensional witch Yūko Ichihara plays an important role in both stories.
This. So much this.
You can enjoy them individually, but once you enjoy them together, both become far richer. It isn’t just about the TRC gang visiting the witch, everything is connected.
Two examples (heavy TRC+xxxHolic spoilers)
TRC’s main antagonist Fei Wang Reed was created by Clow Reed. Who apparently was a lover of Yuuko, the witch of xxxHolic; or at least really close to her. Fei Wang wants the feathers for the power to revive Yuuko, who’s not-quite-alive-or-dead, her time was frozen by Clow.
xxxHolic Watanuki is an alternate existence for the Syaoran who you see travelling in TRC. He had to go back in time to save the Sakura you also see travelling; but he needed to leave “someone” to take his place in the world, so Watanuki was born. In fact everything in xxxHolic boils down to giving that alternate existence of Syaoran some place in the world, so he doesn’t disappear and fuck with causality.
Mushishi and Hellsing also have great worldbuilding, but TRC/xxxHolic is more like a fractal of worlds tied together.
Can’t say about the other series, as I didn’t watch them.
With that out of the way, for people who want an isekai series with good worldbuilding, I’d recommend Log Horizon. AFAIK it was one of the first “trapped in a game” isekai series, and it goes great lengths to explore how game logic interacts with reality. Such as food only having a taste when made by people with a cooking skill, or where the money from loot comes from, or what it means to “die” in the world, etc.
And if you don’t want isekai, there’s The Ancient Magus’ Bride. Sure, younger than things mentioned in the list (the first season is from 2013), but worldbuilding is top notch.
This. So much this.
You can enjoy them individually, but once you enjoy them together, both become far richer. It isn’t just about the TRC gang visiting the witch, everything is connected.
Two examples (heavy TRC+xxxHolic spoilers)
Mushishi and Hellsing also have great worldbuilding, but TRC/xxxHolic is more like a fractal of worlds tied together.
Can’t say about the other series, as I didn’t watch them.
With that out of the way, for people who want an isekai series with good worldbuilding, I’d recommend Log Horizon. AFAIK it was one of the first “trapped in a game” isekai series, and it goes great lengths to explore how game logic interacts with reality. Such as food only having a taste when made by people with a cooking skill, or where the money from loot comes from, or what it means to “die” in the world, etc.
And if you don’t want isekai, there’s The Ancient Magus’ Bride. Sure, younger than things mentioned in the list (the first season is from 2013), but worldbuilding is top notch.