Talk:Mission System/@comment-5759132-20151008120442/@comment-17760674-20151008200914

I'm not sure about the exact time window either, but there's a helpful indicator in-game for it.

You know how when you have enough mana to use a character's skill, the gray hole at the beginning of their HP bar becomes a red gem? When it's flashing, then that character is eligible to continue the current chain. If the red gem is present but not flashing, then the character cannot continue your previous chain, and using the character's skill will start a new chain.

When the red gems flash, they flash slowly at first, and they flash more quickly when you're almost out of time to continue a chain. The timer for continuing chains is based on when you used the previous skill, not when you first started the chain. (As in, if you use an eligible character's skill when their gem is flashing super quickly, then the remaining eligible characters' gems will flash slowly again after you use the skill.) You don't have to worry about getting to max chain in a certain period of time; you only need to worry about the time limit after using each skill.