[The valknut (Old Norse valr, “slain warriors” + knut, “knot”)

This is thought to symbolize the power of the god to bind and unbind, mentioned in the poems and elsewhere. Odin had the power to lay bonds upon the mind, so that men became helpless in battle, and he could also loosen the tensions of fear and strain by his gifts of battle-madness, intoxication, and inspiration.]

The Ulrich Twins adopted this symbol as their COA. Each symbol on it has a meaning or representation.
The vampiric skull represents the “undead” taint that the brothers posses.
The Valknut represents their ability to manipulate the mind of those they interact with through either diplomacy or intimidation.
The red Valknut represents the blood of the slain warriors who oppose them.