The Assassinator, is a unique item. It is an enchanted bow and is the so-called most powerful bow in the world of Mianite in Season One.
It was originally Tom's bow, he obtained it by enchanting a bow at level 30, which gave it the starting enchantments of Infinity I, Unbreaking III and Punch II. He then added Flame I using an enchanted book he obtained containing it, and also added Power V by combining enchanted books with Power until he got a Power V book. The Bow's final enchantments include Flame I, Infinity I, Punch II, Unbreaking III and Power V.
However, it was taken from him on the second purge day, as he was killed by Tucker. Tucker said that he would share it with Jordan as his Stealth Poisoning was what would make it possible to kill him. It would normally take more than 10 shots to kill him, but the poison made his health drop to half a heart, making it possible to kill him with one shot. Later on, Tom got information from a forbidden source, revealing where Jericho had hid the bow. Tom then goes to the bow's location, which happened to be what was left of Borris the Snowman's old room. Tom took it and claimed that he was "borrowing until he came back to the Realm of Mianite," and he "didn't steal it as he didn't find it himself."
It was later shown that Champwan had a similar bow with the same enchantments, which did not include Punch II. However, this is because he dislikes the knock back effect of the punch II, as he feels that the punch creates more distance between the two combatants, and overall makes the fight more difficult.