ok first you need to jump then run up to it hit it 2times and run out but becareful

either go on youtube and search it or withdraw your mission when you die by him and press
start go to files enemy profiles then look for the heartless's name and it will tell you
how to kill it

depends, what's its name? if it's leechgrave, there's a big thread about him going on

i hated i mean HATED this boss destroy all of the tenticle thingys and then he falls and
then u beat him up i belive tat u must lose a little to gain alot though so i let him get
me down to low health then take out the tentical thingys and use my limit on him and make
him cry for his mommy and after tat avoid contact with anything tat moves cause trust me
he will get u down alot and u dont wanna die and do it agian