For each player, you choose from among the permanents that player controls an artifact, a creature, an enchantment, and a planeswalker. Then each player sacrifices all other nonland permanents he or she controls.
The spear thrown by Kytheon's own hand was the weapon that felled his friends.
None of the chosen permanents are targets of Tragic Arrogance.
If a permanent has more than one of the affected types, it can count for any of them. For example, you could choose an artifact creature as the artifact you're sparing, another creature as the creature, and an enchantment creature as the enchantment. Similarly, you could choose an enchantment creature as both the creature and the enchantment that you're sparing, even if the player controls another creature and/or another enchantment.