The Trial Series are a series of artificial Undead created by BOARD from combining human and Undead DNA with machinery and antagonists in Kamen Rider Blade.
- Trial B - An electric-type Undead created by Yoshito Hirose originally to protect his daughter Shiori. However it was reprogrammed by Hiroshi Tennoji to remove any possible threats from the Battle Fight.
- Trial D - A capture-type Undead, it was sent to eliminate Kazuma Kenzaki before he could obtain King form
- Trial E - A shooting-type Undead created from data of Kamen Rider Garren.
- Trial F - An energy-type Undead, it was sent to capture Kenzaki.
- Trial G - A fighting-type Undead based on data of Kamen Rider Leangle, it was used to defeat the Tiger Undead and was capable of fighting all four of the BOARD Kamen Riders.