Blood Stalk

Blood Stalk (ブラッドスターク), is one of the main villains in Kamen Rider Build.

History
Blood Stalk first made contact with Sento shortly after Sento defeated Masahiro Nabeshima as the Mirage Smash by stabbing him in the back with a mysterious tentacle, leaving him stunned. Stalk then used a giant projection of a cobra to retrieve the incapacitated Nabeshima. Gentoku Himuro seems to be aware of Blood Stalk's activity.

Personality
"Why didn't you finish him off...Stalk?" "I'm the game maker. I derive the best strategy by considering every possibility. Everything is going as planned."

- Blood Stalk to Night Rogue

While little is known about him, Blood Stalk is a self-proclaimed strategist. He also seems to have a lot more of an unperturbed attitude compared to the more focused Night Rogue, nonchalantly fooling around even when doing his job as a Faust enforcer. Such is seen when instead of directly engaging Build, he was casually laying back and let Square Smash do most the fighting, until it's the right time for him to interfere by making the Smash grow.

Forms
"Cobra! Mistmatch! Cobra...Co-Cobra... Fire!"

- Transformation announcement

Ability Perimeters: Similar to Night Rogue, Blood Stalk accesses his main form with the Transteam Gun and the Cobra Full Bottle.
 * Height: 201.5 cm
 * Weight: 102.0 kg
 * Punching power: 19.0 t
 * Kicking power: 22.7 t
 * Maximum jump height: 40.0 m
 * Maximum running speed: 100 m. per 4.7 sec.

His stats are not only stronger than most of Build's forms, but also surpass Night Rogue's with only speed being slightly lower than his. Stalk also posseses numerous abilities in this form, such as being able to utilize a tentacle to inject poison into a human and paralyze them. He can also materialize a giant translucent cobra out of thin air to capture and collect victims.

With the Steam Rifle, he can use the following attacks:
 * Devil Steam: He fires a "steam" bullet which will home in on the targeted Smash and injects them with an unknown compound when it hits them.  The compound then causes the Smash to grow to gigantic proportions.

Devices

 * Transteam Gun - Transformation device and personal weapon.
 * Full Bottles - Transformation trinkets.

Weapons

 * Steam Blade - Standard sidearm weapon. Can combine with the Transteam Gun to form the Steam Rifle.

Portrayal
Blood Stalk is voiced by Tetsuo Kanao (金尾 哲夫) who previously voiced as Namakelder in Happiness Charge Pretty Cure!. His suit actor is Kazuya Okada (岡田 和也).

Etymology
To be added.