Does Hollow Bastion have a key hole. If it does how ever the keyhole..

I think Hollow Bastion does but I'm not sure and no Monstro does not have a keyhole, you just have to beat the boss.

For your second question, no Monstro does not have a keyhole. Just beat the boss and you've completed Montro.

Invisible's back in action!!!!! Yes, Hollow Bastion has a keyhole. After you take out Riku/Ansem (and learn the RAGNAROK ability), you are a heartless.

Get to the entrance hall and walk up to Donald, Goofy, and one other (avoid spoilers I shall try). You'll end up in Traverse Town. Talk to Cid, then go down to the Secret Waterway. Talk to the person, then go up to the moon mural. Then there's a cutscene where you get a NAVI-GUMMI and the OATHKEEPER keyblade.

Talk to Cid again. Use the warphole near Traverse Town to get back to Hollow Bastion. Go into the library and watch the Beast and Belle reunite. Talk to Belle afterwards to get the DIVINE ROSE keyblade. Once again, you have to get to the Grand Hall (where you fought Riku/Ansem) and enter the keyhole.

After fighting the Behemoth, you get the OMEGA ARTS accessory. Equip it to Sora. After this, go back to the library and speak to Aerith 3 times to get the Ansem's Reports 2, 4, 6, and 10, and the CURAGA spell. Compete in the Hades Cup for great prizes.

Okay, Hollow Bastion DOES have a keyhole, it's in the Rainbow room in the Grand Hall, and the Grand Hall is somewhere near the Castle Chapel. Note: you will have to defeat two bosses before you can get to it: Ansem Riku and then Behemoth. And don't bother looking for a keyhole in Monstro, it doesn't exist.

Wish you luck,
-knolic-

Once you defeat Malificent, you have to defeat the possessed Riku. There you will find the keyhole.

BUT...you do not seal it. Actually you become a Heartless yourself and have to find your friends (including Kairi) and they will protect you through battle untill you become Sora again.

The keyhole in Hollow Bastion is the doorway to The End of the World (last world). Hope this helped ya.

Oh ya let me tell ya!

Hollow Bastion >does have a key hole<.

When I saw the monster (I think its called behemoth or something) that was guarding it, I almost peed in my pants, turns out its not that hard!

YA, just do all the krud in Hollow Bastion then you fight rikku/ansem and then the behemoth in the big heart thingy, u kill ur self with keyblade cry boohoo (no really u do) and yay!!...

You lock it
tadadadada, super NOMAD!!!

Hey, I saw this girl named sweetsis, I just wanted you to know, you helped me in many ways you'd neva believe when I was a noob in kh.

So I'm sending out my props to SWEETSIS!