The Strongest Demon Lord Tensei Shitara Slime datta ken (Tensura), Rimuru Tempest Vs Guy Crimson
The position of the Strongest Demon Tensei Shitara Slime datta ken is still occupied by Guy Crimson. But as we know that rimuru has a "Mysterious" power and continues to grow every day. Many even said that Rimuru Tempest's strength was at the “Infinite” Level.
When compared to Primordial Devils, the Crimson Guys are the strongest, but when compared to all the Demon Kings in the Tensei Shitara Slime datta ken anime, Rimuru Tempest is the strongest. The reason is very simple, Rimuru has the ability to take the "Strength" of others and then Rimuru's power continues to grow every day. So it can be concluded that Rimuru is the strongest Demon King with an "Infinite" power rating.
Strongest Demon King Tensei Shitara Slime datta ken
There are 2 Demon Kings who are the strongest in the anime Tensei Shitara Slime, here's a brief explanation:
Guy Crimson
Guy Crimson is the strongest and oldest Demon King in the anime Tensei Shitara Slime datta ken. Guy Crimson had the highest standing among the other 7 Primordial Demons. This is because the Crimson Guys' ability is very strong and their 2 subordinates are also very strong. Guy Crimson's subordinates were Hirrari and Mizari who were the 2nd and 3rd rank of the Primordial Demon element.
Guy Crimson has full power over the other Demon Lords. He is very interested in all kinds of unique things including the "Special" powers possessed by other demon lords. Then he is also the strongest among the demon lords Octagram (Demon Lord Of the Octagram). Guy Crimson is a close friend of Diablo/Noir and is his sparring opponent in the underworld (Before being summoned).
Guy Crimson Rank: Special S (SS)
The strength possessed by Guy Crimson has not yet been shown in detail, because Guy Crimson has only been told in a short plot. However, there is a possibility that Guy Crimson will appear in a new season in 2021.
Guy Crimson is the strongest demon lord with a color line (Red) with the main name (before being summoned) is Rouge.
Rimuru Tempest
Rimuru Tempest is one of the strongest demon lords who becomes Guy Crimson's toughest rival. As the MC of the Tensura anime, of course rimuru has a very Over Power power and even now it has been shown a lot. Rimuru had the ability to take the power of others and later he also managed to defeat Clayman and became a part of the Demon Lord Octagram.
Rimuru Tempest had very strong subordinates including the 4 Primordial Demons and Diablo was the strongest. Now by having very strong subordinates and then Rimuru himself has "Infinite" power, it can be concluded that Rimuru is able to compete to be the strongest against Guy Crimson.
Guy Crimson was attracted by Rimuru's abilities, it was even said that he would visit Tempest. There is a possibility that Guy will become Rimuru's Friend, Just as Milim did who until recently had been Rimuru's close “Friend”.
Rimuru Tempest Rank : S ~ SS
Rimuru Tempest will slaughter thousands of enemy soldiers and it's the same with Crimson Guy in the past. Guy Crimsin also slaughtered many enemy soldiers and named him "where there is Guy Crimson there is rain of blood". So, between Rimuru and Guy there are many similarities that make us even more sure that Rimuru will be the strongest (Theory).
It should also be noted that Rimuru Tempest's subordinates are among the strongest characters in the Tensura anime. There were many of Rimuru's subordinates who belonged to the strongest Rank, although above him were the 3 main Demon Lords namely Guy Crimson, Milim and Ramiris.