Eden-DAoC

The 7 point shield specialization skill "Engage" is draining 15 endurance per attack (30 endurance when attacked by a dual wielder). The intended behaviour seems to be 5 endurance per attack.

Find an enemy -> use "Engage" -> aggro the enemy -> watch endurance bar disappear
https://www.youtube.com/watch?v=1TEarlOXdKA

Source?

I was able to find a somewhat aged reference thanks to Lithlet videos:

https://youtu.be/ruSnvwXz0Z4?t=382
2014 video, run it at 50% or slower as the endo bar has a lot of movement.

Lithlet flips on engage at 6:22.
1st attack by vamp is parried, appears to take no endo
Next 3 attacks are blocked and cost 7 endo. but this is because he has been hit by Inexorable Defeat from vamp which increases endo costs by 50%. So 5 base and 7.5 rounding down to 7.

Worth noting it appears to only take endo when specifically a block is successful.

I also quickly checked live and it retains the 5% endo cost and no costs for unblocked attacks.

https://imgur.com/a/vWapvRo

In the Lithlet video you can see him swinging and hitting the opponent at 6.20 and activating engage at 6.22. On eden you have to wait 5 ish seconds after a target has been attacked. I tested with swing speed 4.8 mh, 3.0 mh, large and small shield. Which suggests my swing speed does not impact the engage timer. My shield lifesteal proc also put engage on a 5 second timer.
https://www.youtube.com/watch?v=75R-JRDANRc

Tested against a dual wielding ranger with 1.6 swing speed to get closer to a vamp opponent.
https://www.youtube.com/watch?v=MLWg16MpBpU
5 seconds lockout on engage

Cost will be changed from 15 to 5 next patch. The only on successful block part will have to come later, will leave post open.