In The Keep, The Lycan King will start appearing after all the required waves has been cleared. Players will have a countdown of 30 seconds to prepare themselves before the boss spawns. The Lycan King must be beaten in order to win the map or wave.
In the Campaign, the Lycan King boss fight will start after finishing the 5th wave of the Keep.
As for Survival and Mixed Mode, the boss will only appear after finishing wave 25 of the Keep. Since Survival is now endless, the Lycan King "boss wave" will also start appearing every 5 waves after wave 25.
In Tests of the Lycan, the boss spawns after a 5 second countdown as soon as the player begins the fight.
The Boss Fight
Outside the Keep's walls, The Lycan King starts by pacing around in his stealthed form, a state where he will be invisible from being targeted by any defense. Any damage dealt to or by him (with his Retractable Claws that deals knockback) will be minimal but still dangerous to heroes with squishy-health.
After a tiny chunk of health has been taken, The Lycan King becomes stationary, dropping his stealth and starts howling (which can possibly buffs enemies). This is where there will be a prompt to set a trap by planting a lure within the Keep's walls. There are two locations to choose from but only one can be used in a cycle.
Once the Lure has been planted, the Lycan King will start rushing towards the set location, dropping his resistance to damage and making the players his sole targets. When arrived, the trap will need about 13 seconds to arm for manual detonation. At this point, the Lycan King's attacks will become more aggressive, his howl pulls any nearby heroes toward him to attack and he will also starts to periodically lunge towards any heroes. Any contact with the lunges can be very deadly.
When the Lure is armed, the Lycan King needs to be attracted by the player to a position in proximity to the Lure where you can manually detonate it. When detonated, the Lycan King will be stunned and players will be able to attack him without any worries. After a certain amount of damage has been dealt or enough time has passed, the Lycan King will rush back outside the Keep's walls and the cycle begins again until he run out of health or the core is destroyed.
Test of the Lycan
In Test of the Lycan modes, there are some minor differences with how the Lycan King's behaviour and abilities work namely -
The Lycan King's stealth is now called "Sanguine Cloak". There is a counter that shows how much damage is done to the Cloak before the boss enters the next phase.
The Lycan King's howling becomes an "Empowering Shriek". Unlike regular howling, the boss will be immune to any forms of damage while he is in this state. (With the exception of the howls after the traps are set.)
The Lures are now referred to as "Ichorous Traps". The only difference from its regular counterpart is there is no time required for arming. The traps will be armed as soon as the Lycan King arrives within the Keep's walls.
The Lycan King cannot be damaged from afar. Players must be within the range of an aura emmited by the boss to be able to deal any damage.