The gladius is a Slayer monster, requiring 81 Slayer to combat. Described as "highly mobile", it is a member of the Order of Ascension.
When fighting the Gladii, they will always teleport backwards in an attempt to gain enough distance between them and the player for a charge attack. If the player is far enough from the Gladius, it will charge at them in a L-shaped pattern, much like the Knight piece in a game of chess. While it does no damage, it does stun and bind the player for 3 seconds and often proves to be a hindrance. To minimise the amount of stuns they perform, players can either chase the Gladius or use Anticipation and Freedom to cancel out their stuns and binds. Chasing them is not recommended unless playing on Legacy Mode, as players with sufficient weaponry may deal too much damage in a short period of time and cause the Gladii to stun them.
Alternatively, one can safe spot them with the many tables in the dungeon, as long as they are placed in a position where they cannot charge. The only downside to this is that most of these areas also have Capsarii to heal them.
Gladius are one of the few monsters capable of stunning their target, the others being Nex during her ice phase, Vyrewatch (until meeting Vanescula in The Branches of Darkmeyer), the Kalphite King, and most ability-using monsters.
When stunned the first time by a Gladius, the player is stunned and bound for 3 seconds. However, upon further stuns as long as the player keeps attacking nearby Gladii, they will only have a 1-2 second stun with a 3 second bind.