The Mad Alchemist. This Mage Boss will appear in Boss Monster: The Next Level.
Dr. Timebender's Level Up Ability works very similarly to the All Seeing Eye, so having cards that can allow the player to gain access to Spell Cards regularly help this Boss' ability to be used more often. Dr. Timebender works well against other Mage Bosses that can gain access to Spell cards with ease, like Kazanna or Nicolius.
It is not known whether Dr. Timebender is meant to appear as Dr. Wily of Megaman, or Dr. Eggman of Sonic the Hedgehog, but it simply appears that he is cast to appear in the same vein.