Catching Monsters Easily

Do not give Ovaseeds to your monsters. Instead, throw them at monsters you need in the Tower to get their eggs. The game will not tell you what the egg is called.

Getting The Dragon Kings

Get a Kid to the Dragon stage or catch a Dragon in the basement floors. Then, catch a Bomber and evolve it into a Daedalus (they turn into the upper forms at level 10). Fuse them together to get Blith. Next, get a Daedalus and Vevil (Vevils are found around the 90th basement floor). Fuse them to get Yankash. The other Dragon King is obtained by the same process, but use a Glacier to fuse with the Daedalus or Vevil.

Get A Kid Egg

Find all three bells by defeating three special Souvenirs. After you give them all to the old man, go on a quest and return. Go find the old man and he will give you a Kid egg.

Capture Rare Monsters

If you have an Ovaseed, just throw it at the monster you want to catch. This is useful when catching Souvenirs and Guardians.

Getting An Almost Invincible Monster

Catch an Alloyer and an Arachne. Make them both transform into their upper forms, then fuse them. You now need a Souvenir. Once you get one, fuse that with your new monster (hopefully it is the transformation of Arachne) to get a monster with double speed. Next, you need a Barong. Fuse that with the new monster (evolution of Arachne with double speed) to get an evolution of Archne with an ability that lets it gain extra experience. You should now have a powerful monster. To make it even more powerful, get extra Arachnes and Alloyers and fuse them with it. Just make sure you constantly have the evolution of Arachne. After you get Gance, fuse your new monster with it when ready. Your monster will be invincible when it transforms into S-Gance. Get Mai-Soul and fuse it S-Gance (if you do not mind losing it), to become even stronger.