I came across something somewhere for CoD that said an ID wouldn't spawn a Devil Shard until it reached the level that the shard it was made from was created. Let me tell you why I NEEDED to verify/debunk this.

I have spent half a spiral notebook and lotsa hours trying to FULLY understand the "mini-game"-esque world of Innocent Devils. I have noticed that 15 levels gained [64-79, btw] on a pumkin ID (the 2nd easiest to use for this kind of project because all his 4 stats are and remain even), the only difference was the higher level spawned shard produced an ID with +1 heart and +2 to his stats. That's it. The difference between a Level 60-ish spawned shard and a level 99 spawned shard is significant, but hardly worth the time to level up.
Generations, however, give much better. Example, a 2nd gen Pumpkin's stats upon creation (first shard spawned, too) were DOUBLE that of the original, and his hearts started at +10. A combo of the two, in my expiriments, seemed the next step, so I took the original to Lv99 until I used a shard, made a 2 gen, took HIM to lv99 where he would FINALLY drop a shard after a certain number of kills, etc. Unless you have ZERO other games to play, life to lead, etc., this took entirely too long to be feasable.

***just to be clear, generations do NOT affect the base additions to Hectors stats, just Heart count, the IDs stats, and which stats it's strong/weak in {i.e. Using a Speed Mail dropped shard will yield more to agility if it's used for an Iytei, than a Golem dropped one will given same gen and near same level)

Instead, record your Original's stats and hearts (at any level is ok), then as soon as they drop a shard at (random number) Lv50, warp to Julia's and start in on it. I reccomend using a different Evo path, btw, and work that 2 gen until it drops a shard (dont forget to compare it's stats w/ those you recorded from your original when he's the same level), go get it and start your new 3 gen, repeat, changing paths as often as you can to create a good all-around ID. Of course, you can stop working on this to level up/evolve anything, I typically went to one of my little level-up spots (think any stairs, people) as soon as I got a new ID Type in my new save, and got me a 5-7 gen and used that as my base and delete all the previous ones, taking him to a good final evo, then using the FIRST shard he would spawn (lowest level), worked others up to whatever.

It looks like there's alot of overlooking here. True, the Pumpkin ID has no useful abilities, he can't attack worth a dad-gum, and his hearts barely break 100 at level 70+. However, the stat bonuses he gives to Hector can be flippin SWEET! I suggest this. Take your Pumpkin ID to your favorite level up/crystal getting spot (mine is Infinite Corridor behind the door you open with brute force lv2, in front of the save room) and fart around until he's high level and drops a shard, create an ID from that shard, rinse and repeat until you have a high gen. The higher the level he is when he drops the shard and the higher the generation, the more hearts he'll have (that way he won't die so easy). When you're happy, level him to 99, equip the rare ring and either the clown suit or the prince's clothes and go rare item hunting. Trust me, you'll have WAY better results than any other way.

Your Innocent Devil can and WILL evolve before all of his abilities for his current evolution are learned. To avoid this, make sure to go to his evolution tree and check his ability list for his current evolution to make sure there are no lines of question marks. If there are, turn off your evolution crystals for him (done by going into the summon window and pressing left on the d-pad) until that ability is learned, then just turn them back on to evolve. You CANNOT go back to learn an ability. He cannot un-evolve, so if you miss an ability, you're burnt. You have to start over.