@Azurolu Yes. Please guide.

@metaden Here is mastodon, it's one of the many platforms of the fediverse and it's Gargron's project. mastodon.social is Gargron's instance. An instance is a server that anyone can set up and link to the rest of the fediverse: For example, I'm on the mastodon.xyz instance made by @TheKinrar Each instance has its own set of rules.
Mastodon is not the only platform of the fediverse, there are also GNU/Social instances and Pleroma instances, which are free speech oriented.

@metaden I suggest you follow @Gargron because he's your instance's admin, @lain to keep up with the development of pleroma and that will probably lead you to discover more people in the anime/manga and other kind of nerdy stuff etc community.
I also suggest you take a look at @Technowix's instance niu.moe, which is a anime based instance you'd probably like, with a really cool admin and active userbase.
instances.mastodon.xyz is where you'll find a list of (mastodon only) instances, by @TheKinrar.

@Azurolu How do you check an instance without registering?

@metaden Also, since I see you're from Japan here are some cool and funny japanese users you could add: @kiki @estpls @NSXG
Even if you're going to change instance soon, you can follow them here and import/export your followings from the settings (called preferences on mastodon, the gear at the top of the search bar).