Capt. KirschHeels Sentry is a former captain of the Guard to King Sombra's right.
On Equestria realm,He's a vicious but dark Pegasus and endorse of contributes King Sombra and always wearing a cape and an armor that makes him more like a knight with a risky feats as King Sombra's soldier.
He,unlike Flash Sentry, is very judgmental, cold, ruthless, and very faithful with Splurgk the purple Smooze, Hallow Lodge The Buffalo, The Demon Bros: Heat and Snow Demon, Forest Demon, and even Malice the Goblin to guard the Another version of the Tree of Harmony from any harm.
On Equestrian Girl, I'm thinking that in his human form, his skin color is grey and his hair are pale rose and bears to have an uncanny resemblance to Flash Sentry and his hands got long silvery nails.