Personal Icon
The model bears a personal Icon of the Chaos Gods. The Icon will be aligned with whatever power the model bears the Mark of. The personal Icon can be used as a focus for Daemon Summoning just like unit Icons.
Special Icons
Daemon Icon. May only be carried by a unit of Chosen bearing the Mark of Chaos Undivided. A Daemon Icon is a Chaos Undivided Icon which, as well as acting as a focus for summoning Daemons normally, is a powerful conjuration and binding tool as well. At the start of the game a single nominated Daemon unit may be enslaved within the Icon. At the start of the Chaos player's turn this unit can be automatically summoned without making a Reserves roll. The Daemons will not scatter and the template is placed in contact with the Icon. The unit can move in the Movement phase and assault as normal.
Icon of Chaos Undivided. May only be carried by a unit of Chosen bearing the Mark of Chaos Undivided. A Chaos Icon is a powerful focus for the energies of Chaos Undivided. It can be used to summon Daemons onto the battlefield as normal and in addition any unit or model bearing the Mark of Chaos Undivided with a model within 6" of the Icon becomes Fearless.
Errata — Chapter Approved: Codex: Chaos Space Marines Q&A (v3.0): If a successful Daemon Summoning roll is made but all Icon Bearers in the army are inside a transport vehicle (such as a Rhino), the Daemons do not arrive that turn — icons in vehicles cannot be used to summon, and this applies even if a different Icon Bearer is out of a vehicle elsewhere, if it's the in-vehicle Icon that would otherwise be used. A model bearing an Icon may still be used as a summoning focus while it's locked in hand-to-hand combat, although placing the summoned Daemons may be made difficult by the presence of the enemy. A Chosen Chaos Space Marine carrying a Special Icon does not need to be an Aspiring Champion.