I became strongest in the world by summoning Heroes with my exclusive Gatcha is a Manga/Manhwa/Manhua in english language, Action series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Alright!! UR(Ultimate Rare) king Arthur has come! In a world where demons are rampant due to an "invasion" from another dimension, there was a man who continuously played gacha games. His name was Yanagi Kamuri. A gacha fanatic, totally consumed by his love for it, he was a true gacha addict. One day, Kamuri faced an attack by demons. Only those with skills, known as the Gifted, could fight against them. Without any skills, Kamuri had only one option: to flee. During which he encountered Zeri, a princess from another world, a true royal inheriting her royal family skills. This encounter greatly changed Kamuri's fate. Amidst another demon attack, Zeri entrusted Kamuri with a skill she couldn't master herself. Combined with Kamuri's obsession with gacha, this skill transformed into a unique gacha skill only he could use. To save Zeri and fulfill his dream of endless gacha pulls, Kamuri begins his counterattack! With desperate do or die gambles, he summons the mightiest of heroes!