I think enlightenment stacks since the time you create the 1st character on your account at a rate of 0.4M a day, but you can only stack 12 days worth of it. So the maximum enlightenment you can have is 12 x 0.4M = 4.8M, close to the 5M. Just like the CP pool, enlightenment pool is per account, not per character. Once you earn a CP you can use it on all your characters, even if they are below level 50. During the enlightenment any XP you gain contributes 4x to the CP gain, but the multiplier does not apply to skills; those gain XP at the normal rate. It's quite easy to gain XP. The daily random dungeon completion alone nets you 100K XP of the bat, which consumes 400K, or a day's worth of enlightenment. All mobs you kill and quests you complete add to that. Quests in the gold and silver areas give between 5-20K XP, objective completion probably around 5K as well, mobs several hundred XP. So you will probably run out of your 12 days worth of enlightenment quite fast, and then just use up all your daily allotment. Enjoy your yolk sack, hatchling!

They give you a full 4.8 million points automatically, as it's your first Champion Rank character. You could have grinded to level 50 in two days after you bought the game, and would have still had 4.8 million.