As far as I know a warden marks his/her enemies in order to exploit Warden's Fury and Warden's Grasp immediate at-wills. But in Primal Power, page 95, Daily Evocations lvl 5, Lifebind Attack states:
Effect: While the target is marked by you, its penalty to attack rolls for the marked condition is -5 instead of -2.
Is there something I'm missing? Where is it stated that warden's mark acts the same as fighter's?
Marked is a condition in 4e. It can be applied by most Defender classes, and is how they're able to "defend". The definition for the Marked condition includes the following:
The creature takes a -2 penalty to attack rolls for any attack that doesn’t include the marking creature as a target. (Player's Handbook, p. 277)
This means that the Warden's mark is the same as the Fighter's because they are both marks. The Warden's class feature does not mimic the Fighter's class feature; instead both class features make use of the same non-class-specific "mark" mechanic (even Rogues can pick up powers which let them use marks).
