Small jungler buff: Bladed Armor... Can we reduce the % but make it stack?

It does 1% damage per second for 2 seconds.

For slower and tankier junglers having it do 0.5%, stacking cumulative to 3% per second. So the more the monster attacks you the harder you hit back. Most fast junglers doesn't get hit much more than 3x per camp per monster, but slower clearers could get a bit of a buff through just buffing this mastery a little.

It's still % of the monster's **current ** health, so it's shouldn't get too OP against baron and drake.

Another suggestion is just to make it magic damage rather than physical as monsters generally doesn't have MR.