Discovered something about Amakusa a while ago that I tested again at a friends house this week.
Amakusa is beastly in SSV spirit and here is why....
When you enter Mu no Kyouchi and you are farther away from the opponent, you can input his fireball. When the fireball is hitting the opponent, input the Issen slash. What happens now is the fireball hits multiple times and does ALOT of damage (when I set the meditation bar to 100%, the fireball alone did half a life). Now when the Issen hits (after the fireball) it did a full bar of damage in total.
This can be effective, as you could do a jump attack, activate Mu no Kyouchi, do standing attack, cancel to backward teleport and do the following in the above paragraph. Even at 20% meditation by default, this technique can do an absurd amount of damage.