Orb of Mages, Sphere of Magic, Magic Familiar, Arcanist Orb, call it what you want! it is the convergence of frost and fire into the Arcane, a pure core of elemental energy. After sketching for a good long time and some layer work I came up with this, hope you enjoy it, I made it for Antonidas the Arcane Master in my Duel of Gods map.
Antonidas has a passive that allows him to select which element to pour into his autoattacks (Fire. Frost or the Arcane, and the orbs interact with it).
Arcanist Orb: places an incontrollable, immobile and invulnerable orb up into a location, the element of the orb will depend on your current set. The orb will attack nearby enemies each 1.5 seconds for 33 magic damage.
Lasts for 75 seconds.
The orb destroys itself after attacking a structure 3 times or after attacking an enemy hero 9 times.
Fire: deals 50% extra damage and half of the damage splashes in a 125 AoE.
Frost: applies frost for 2 seconds, roots minions and lesser units for 2 seconds.
Arcane: restores a 0.75% of your mana per hit and deals true damage.
Cooldown: 15 seconds