I'm not sure specifically what 'ttigraas web novel' is about as it could be a very specific or even a relatively unknown web novel. It might be about various things like adventure, fantasy, romance or a mix of different genres.
Among the main characters besides Rimuru are Gobta. He is a goblin who is rather comical at times but also shows growth throughout the story. Then there is Diablo, a very powerful demon who becomes Rimuru's subordinate. His power and knowledge contribute to Rimuru's rise in the world of the novel. There are also other characters like Milim, a dragonoid with a child - like personality who has her own impact on the overall plot.
There's Veldora. He's a powerful dragon sealed within Rimuru's stomach at first. His presence has a great impact on Rimuru's growth and the story. Then there's Shion, a strong ogre who becomes one of Rimuru's loyal followers. She's known for her combat abilities. Also, Benimaru, a kijin, is an important character. He plays a key role in the development of Tempest.
I'm not sure where you can read 'ttigraas web novel'. It might be available on some specific web novel platforms. You could try searching for it on popular web novel websites.
Rimuru is very strong in the manga. He starts off with some unique abilities and keeps getting stronger through different events and encounters. His strength is not just physical but also in his strategic thinking and leadership skills.
One of Rimuru's notable feats is his leadership in building his own nation. He manages to bring together different races and create a harmonious society. This shows his charisma and intelligence in governance. Also, his combat feats are remarkable. He can use his unique slime abilities in creative ways during battles, like forming various weapons and defenses out of his slime body.
The Rimuru Web Novel is centered around Rimuru's growth and development. Rimuru starts as a weak slime but gradually becomes very powerful. He meets different characters, forms alliances, and overcomes many challenges in the fantasy world he inhabits. For example, he has to deal with power - hungry villains and complex political situations within his territory.