There are 2 different situations:
When folks use alternative forms or specify powers based on story arcs from ongoing HST series, it's up to the mod's call.
Pretty much, we lock outdated dupe threads. That's why we warn users to search topics beforehand when making threads like Ichigo vs Luffy.
- Pre Time Skip Luffy vs Pre Time Skip Ichigo
- Zombie Luffy vs Hollow Ichigo
- Current Luffy vs Current Ichigo
There is no specific rule. Rather it's a general rule of thumb that mods go by. I ask Sonata prior to locking these type of threads. Usually Sonata tells me to lock the spammy threads and outdated threads.
With threads like Gremmy and they have past the 100 Post Mark and Unlocked for another 100 posts, there can be an exception, but it has be significant amount of feats revealed in the ongoing manga. Remember the Roronoa Zoro Vs Zaraki Kempachi thread, when bumped it, the outcome was severely changed in favor of Kenpachi due to developments in Bleach. That thread's fate is unknown given that One Piece and Bleach are ongoing. You guys need to watch how you post. Now, it's more about posting carefully and watching the post count. I do delete my posts before 100 post mark after telling users that they violated certain rules.
Right now, you just got to wait or post a different battle thread with Gremmy and another combatant to continue the momentum. Then, come back to the Gremmy thread once new things are brought up.
For the battle rules, Dream, Sonata, and I worked on it to make it brief with brevity. That way, it's flexible for interpretation. That's why we don't go too deep in setting conditions for locked and dupe threads. It's pretty much up to the mods' call.