Well, it's not really an unlockable, but it a list of all the bosses and where they are & how to get them (sorry the names are in Japanese)
| Unlockable: | How to unlock: |
| Tangrowth | Your final test at Ranger School |
| Toxicroak | Attacks you while distroying the machines in the city developed by Team Yamiyami (the Evil Group) |
| Rampardos | In the Mountain Range, Team Yamiyami will send two at you, one for your leader, one for you |
| Drapion | On Team Yamiyami's boat, after a bunch of grunt battles the Admin will send it |
| Spiritomb | Appers while searching in the Almia Caves |
| Froslass | At the end of the Lamia Palace, a Team Yamiyami Commander will be there, and send it at you |
| Lucario | A few rooms ahead of Froslass, Lucario is Guarding the Water Drop. He challanges you to a match. |
| Infernape | On Boil Island, you'll come across a Team Yamiyami Commander and two grunts. The two grunts send Monfernos at you, and the Commander sends Infernape |
| Heatran | A few rooms after Infernape, Heatran is Guarding the Fire Drop, It challanges you to a match. |
| Kingdra | While underwater; a bunch of Team Yamiyami grunts are blocking a few Wailord. When you're about to free the last one, their Kingdra attacks you |
| Glicsor | In Team Yamiyami's headquarters, you face tons of grunt battles; and this one. It's the Admin from the boat. |
| Cresselia | Inside the temple in the Haruba Desert, Cresselia protects the Crecent Moon Stone. She challanges you. |
| Magnazone | After Cresselia, you are forced to trade the stone for your captured friends. After, they drop Magnazone on you. |
| Electivire | After returning to Ranger base, the same Admin who took the Moon plate from you, is at the base with Electivire. |
| Garchomp | After Electivire, you run upstairs to find Team Yamiyami holding the Scientist hostage. They send Garchomp at you. |
| Rhyperior | At the Team Yamiyami Tower, after facing MANY grunts, near the top, a Commander attacks you with Rhyperior |
| Gallade | After defeating Rhyperior, on the next floor is Gallade |
| Magmortar | After defeating Gallade, the 3rd floor is Magmortar |
| Rhyperior, Gallade, & Magmortar | Rhyperior, Gallade, & Magmortar, all the Commanders will come to you infuriated, and attack you with Rhyperior, Gallade, & Magmortar. |
| Dusknoir | On the last floor after Rhyperior, Gallade, & Magmortar, the Boss of Team Yamiyami will be (sorta) impressed but mad, and attack you with Dusknoir |
| Darkai | After Dusknoir, Darkai Appers, and immediatly you battle it |
| Regigigas | After capturing all 266 pokemon (not including Dialga, Palkia and Shaymin) make your way over to the Hippodon Temple; a new room will be open, and Regigigas will be there. |
| Dialga | Unknown |
| Palkia | Unknown |
| Shaymin | Unknown |
