Need it a bit more specific, but this works
Assuming no CIS, infinite stamina and environmental obstructions. Character A is the character getting speed-blitz
Case I: Character A is in in H2H combat with the opponent, equal skill level, 1 metre distance
Case II: Character A is in extended melee-weapon combat with the opponent, equal skill level, 5 metres
Case III: Character A is using a projectile-based weapon firing at a speed near instantaneous from their own perspective, low skill level, starting distance 20 metres
Case IV: Character A is using a projectile-based weapon firing at a speed near instantaneous from their own perspective, military level training, starting distance 20 metres
Case V: Character A has thought-based ability capable of oneshotting the opponent while the opponent has a projectile-based weapon firing at a speed near instantaneous from their own perspective, starting distance 10 metres.
Case VI: Character A has thought-based ability capable of oneshotting the opponent while the opponent can oneshot Character A by melee combat, starting distance 10 metres
Case VII: Both Character A and their opponent have thought-based abilties capable of oneshotting each other.
and so on...
Stuff like this, we need to define the MINIMUM speed gap required to never get hit by Character A OR hitting and KOing Character A before they can respond. If a specific speed type or multiple speed types are needing definitions in a specific case, please state them all.
