Yep it's mainly base on their powel lvls and the more espers fight the more unstable they became that's where the guides came in they can cleanse the espers. If an esper can't get guiding on time they could go berserk and die that's why guides are as important as espers. And they rank the guides as well like the higher your rank is the higher your guiding works. Some of the guide verses have something called "matching rates" tho it's like even if the guide rank is low if the matching rate is high enough it would be as effective as getting guiding from an S rank guide. In some cases the more matching rate they have they more they feel GOOD while getting guide.
Chinese guideverse features Sentinas and Guides. Both Sentinals and guides abilities manifest as a sentient animal companion that only ability users can see. Often used on missions to assist with infiltration, scouting, communication, and attack. Depending on the story they can be physical or purely spectral manifestation of the Sentinal/Guides power. Animal compnions is one of the most common ways to identify an ability user.
Sentinals are power users that typically have increased physical traits and enhanced senses but over time become unstable/corrupted without treatment from guides. Over time if left untreated Sentinals become aggressive, hyper sensitive and will eventually die misserabley in pain.
Guides are ability users that don't typically have any enhancements or abilities beyound being able to heal/purify Sentinals. They tend to be more rare then Sentinals but that depends on the story. How well they can guide is determined by their rank and compatibility with an individual Sentinal.
Both Sentinals and Guides are ranked using F-S grade system which represents their ability strength. Generaly only Guides of a similar or higher level can effectively guide/treat a Sentinel. So an A rank Sentinel will seek out a B or higher ranked guide. Exceptions can occur if a Guide and Sentinel have high compatibility which will significantly improve guiding efficiency between the two. Sometimes high compatibility is more important than high rank. Sentinals go crazy for Guides with a high compatibility with them. Not just because of improved guiding efficiency but also because it feels better. Sometimes to the point of intense sexual pleasure. But if the rank difference is to great the boost from high compatibility may not be enough for the Sentinel and they will look for a stronger guide.
Mostly but Sentinel/Guide is Chinese and Esper/Guide is typically Korean (some japanese). Espers tend to be more similar to hunters/super heroes with unique abilities like fire, explosions, mind reading etc. Most
Chinese Sentinals don't have fantastical abilities just enhanced physicals and senses (sight, sound, taste, etc) with the addition of an animal manifestation. Espers, unless that is their ability don't have the animal manifestation of their powers.
The setting between the two also follow different trends. Espers tend to barrow heavily from hunter/gate settings whereas Sentinals tend to barrow more from sci-fi, gov agency (secret agent, spy, etc) action settings.
So while both are similar there are some differences worth mentioning. Although there aren't a lot of options for comics so probably not worth being too picky. For those who like webnovels there's a lot of options, especially for Chinese Sentinals as they've been around longest.
Can anyone explain how does this guide world works? .... I'm new to this concept, so I can't understand a single thing they are saying.... What is guide? And how they are classified as s or d or many more idk... How stronger they are?.... I just can't relate to anything ╥﹏╥.... Someone plzz help if u know ಥ_ಥ
EDIT : Thank you guys are helping to understand the concept ❀(*´▽`*)❀..... I really appreciate ur replies (◍•ᴗ•◍)..... Thanks a lot