Once DDTankers reach level 22, the "Jewel" button will become available, as you level up more Jewel Slots will also be unlocked. Jewels plays an essential role when battling as they provide great boost to your battle abilities.
There are three types of Jewels: Attack Type (Yellow), Defense Type (Blue), and Special Type (Purple)!
As their type suggests, attack type jewels will increase stats such as your attack power, critical chance, critical power, penetration. Defense type jewels will increase your HP, Armor, Speed or Rage.
Special type jewels are a bit, well, special! Having less slot than the others, but the stats they provide are huge! You may also have up to three preset loadouts to conveniently switch between different setups before heading into battle!
Just like you may combine enhancers, you may also combine low level Jewels into higher level jewels!