Experience points (Pre-Update 20)

Pre-Update 20 value for archival purpose.

After TR
Experience points required to level is increased after your True Reincarnation (TR).

After two True Reincarnations, experience required is even more.

Breakdown
After your first TR, XP needed per rank is increased by (5 * Current level) %. After your second TR, it is increased by (10 * Current level) %.