Ok just to let you know you can get wild monsters to join your team just get one of your marshals and have him wandering around in different kinds of terrin durring the game, I recommend having them wander around in the forest/grass more then anything thats where most wild enemies show up and all you have to do to make the wild monsters join your team is defeat them in battle.
For a good team you will need to beat the game once.Get the Gaia the fierce knight and Dark Magician and use the Black Luster Ritual on them both(need to beat game twice to get two of them)when you use it on Gaia, he will become the Black luster Soldier, Dark Magician will become the Black Magician of Chaos if you get a Summoned Skull use it with your team as it hits all machine monsters hard.I've beat the game may times with this team,Black Luster Soldier, Black Magician of Chaos, and summoned skull-all their levels are as high as they can go-and I have gotten all tyhe god items.Hope this helps.
To do this you have to have beaten the game atleast once.At the last mission, equip the god item, Slifers orb, soul of Oblisk, or eye of Ra to a monster.When you battle the god monster summon your own god and defeat it.After you defeat it the guy that summons it will come back and will bring back the god monster and it will be much harder since it is level 99 this time.
After completing either yugi's or kaiba's story you get a special summoning item ,that enables you to summon egyptian gods.
If you start with yugi you get obelisk the tormentor at the end, and if you do kaiba's story , you get slifer the sky dragon, if you started kaibas story first you can equip yugi with his monsters plus the egyptian god monsters.
To beat the Egyptian Gods, I suggest you use the Dark Magician or Dark Magician #2, Dark Magician Girl and Magician Of Black Chaos, equip them with Book Of Secret Arts then use their special to inflict heavy damage!
If you press up up down down left right left right on the d-pad then press b a you recive from 537 to 540 coins, varries some times you have to do this in order on open ground not on a player or a city/village or any other building.