You must defeat the Chapter 7 boss.

You must defeat the Chapter 3 boss.

You must defeat the Chapter 8 boss.

You must defeat the Chapter 11 boss.

You must defeat the last boss.

You must defeat the Chapter 12 boss.

You must defeat the Chapter 9 boss.

You must defeat the Chapter 5 boss.

You have to finish Chapter 4 of Story Mode.

After you complete a level such as a free mission, you notice your rank. If you get an ‘S’ rank (1000 total points) You get get special Biochemical Items for Item Creations by ‘Pete’. You get a different item for every mission. On the Mission were you have to Kill De Ragen you get the Biochemical Item ‘DE Ragen’.

Please note this only works for levels 15+. Once you get to level 15, do the “Ruler of the Plains” mission from the Parum flyer base. To get an ‘S’ you need to kill all monsters and the dragon in under I believe 7 minutes. On the first cave entrance, go to the left and kill the two dragons, this always had me get an ‘A’ if i didn’t. The rest is easy. A hint for the De Ragan slaying, get rising strike to level 11 and push Y right after it finishes to use a special combo.
Attack the dragon in front of its chest by its neck: you will do triple damage hitting his neck, chest and feet. If you get a good sword you can hit up to 1,000 damage per combo. This way, you can kill the De Ragan before it can attack like I did. If you get an ‘S’, you should receive a De Ragan which is a head decor or a +8 to all Partner Machine stats but also -8 to attack. YOu might also receive other items like technics or discs. You make about 10k meseta from one run. Or if you don’t sell the head you get about 5k Meseta because the De Ragan decor is worth 5k to a shop vendor. I personally used it all and just kept doing the mission until I ended up with about 600k. Wasn’t too hard took me about an hour of gameplay.

Your partner machine can evolve at certain levels. I did some testing and I discovered that the levels are production level 10, 20, and 30. 10 and 20 just do better synthesis, while 30 allows your PM to go into battle. Be careful, the stats which you give to your PM will determine what it looks like, how it fights, and what weapon it uses. I ended up with a mini-tooth-fairy looking little girl with a shotgun. It does a 200, 200, and another 200 on a direct hit on the De Ragan. I recommend buying Carline which does all stats +8 except attack, and normal Photons which do +2 for everything except -2 for armor. If a stat is leveled with now red XP it cannot back level so it can’t reduce stats.