This answer states that the Sword of Summoning "has a chance … to summon a friendly minion [when you kill an opponent] in it's place, which can act as a meat shield to protect you and kill enemies".
How does this work? What is the probability of summoning a friendly minion?
Best Answer
Upon killing any unit, there is a 50% chance of summoning a friendly minion.
Note however that this unit must be killed by you, the player, and not by any existing allies. Thus, it is impossible to have more than one friendly minion at a time (except on the Hell level).