He is the prince of Rosalia.
He ais recruitable at the "Monster Training 3", then, he is recruitable at Wilminton Harbor.
Neidhart is a great asset, he has 20 Strength, with a plus, he comes already with his Kayakis Spear(45 Attack Power, Dragon Banisher Art) that is powerful enough to replace Dragon Spear - Smaug(47 Attack Power, Round Slicer Art), as Dragon Banisher is WAY BETTER than Round Slicer. His cosplay item, War God Armor gears him in all areas with 22 Strength and 19 Magic, this is very insane! He can also do great with Big Swords.
Like Ellen, Neidhart blooms perfectly at the time he joins, as his cosplay item is easily obtained, as no boss battles are necessary.