This is my (expanded) view on how this works...
This is a two-part effect, obviously. The first part can be triggered at any point during the challenges phase to stand a kneeling Viper.
The second part is the one that's trickier due to its specific verbiage. The second part can only be triggered under the following conditions:
- There is currently a challenge underway (whether you're participating or not - we have to consider Melee here)
- The Viper WAS kneeling and you've used one token to stand him in the SAME window
Then, and only then, can you discard that second token to raise the claim value on any player's plot card (again, this must be the SAME window where you discarded the first token).
Regarding defense... If you're taking the chance, you could do this on defense and raise the attacker's claim from 2 to 3 because you have Red Vengeance in hand and 2 influence available. Low down dirty trick... but this is Martell we're talking about.
Edited by doulos2k, 06 November 2013 - 06:12 PM.