That’s the thing: Sorcerers aren’t only summoners. Sorcerers is a general term, it isn’t strictly and only about summoning spirits, it’s just basically someone who practices magic in a more evil/dark way. For example, a sorcerer can practice necromancy (I think originally the word necromancy didn’t even exist actually, and that it was just called “sorcery”).
Assassins
Assassins (Arabic: ٱلْحَشَّاشِين al-Ḥashāshīn) is the common name used to refer to an Islamic sect formally known as the Nizari Ismailis. Often described as a secret order led by a mysterious "Old Man of the Mountain", the Nizari Ismailis formed in the late 11th century after a split within Ismailism – a branch of Shia Islam. The Nizaris posed a strategic threat to Sunni Seljuq authority by capturing and inhabiting several mountain fortresses throughout Persia and later Syria, under the leadersh...