Fargo's Mod/Shadow Force

The Shadow Force is a craftable post-Moon Lord. In depth, it provides

Greatly enhances Lightning Aura and Flameburst Sentries

Grants the ability to climb and dash (also through walls), gain first strike buff (+500% Damage once) after throwing smoke bomb or teleporting (like rod of discord)

You have an aura of 3 shadow orbs (attacking one summons evil energy to attack enemies)

Attacks could inflict Darkness and minions could preform scythe attack

Killing enemies creates bones (or from bosses every 10% HP lost); collecting it summons a friendly dungeon guardian scaling with enemy hp

Summons a Flameburst minions at your mouse that fire after charging and manifest from your shadows while attacking ; then will act as a sentry and repeat (3 sentries max)

Trivia

 * The tooltip is a reference to a quote from Entry Number 17 in Undertale.