They’re the first miniboss you’ll find in Sonic Frontiers
For the most part, Sonic Frontiers enemies can be broken down into three silos: big bosses at the end of an island/area, minibosses, and regular enemies. Guardians will serve as said minibosses, who generally grant players with gears that you can then use to unlock Cyber Space levels (which provide vault keys for Chaos Emeralds).
Naturally, you’ll be fighting a lot of Guardians, including the Asura type, which are coincidentally the “first real miniboss” you’ll encounter at the start of the first island: after the tutorial miniboss.
Getting on top of the Asura Guardian
Like several other gigantic enemies in Sonic Frontiers, you may need to wait for them to actually try and attack you: then run up one of their appendages. In this case, it’s the Asura’s arm you’re going to be looking for.
After the arm slams down boost up into the blue rings, which will propel you toward the Asura’s head: where the real damage can be dealt. If you get shaken off, try and boost with R2/RT to get some air, and stay on the Asura’s head.
Taking out the three towers
Once you’re on top, you can do actual damage to the Asura Guardian. The areas you’re going to be aiming for are the three monoliths/spires, which can take a certain amount of damage before being destroyed. Once each one goes down, the head will become increasingly armed with more defenses (including rings around each spire, and projectiles).
The easiest way to dodge/avoid all of this is to just attack the spires with a ranged ability. Sonic earns one very early on that allows players to hold the L2/LT button and sort of “kick” energy blasts at enemies (like the screen above). Doing that outside of the security laser grid will let you blast each spire safely.
When Asura tries to shake you off, immediately double jump in the air and boost (again, R2/RT) to try and stick around without falling to the ground. If you do fall off, repeat the steps above to get back on the Asura’s head.