If a unit is moved to a battlefield as a result of a spell, are they considered either attacking or defending?

Yes, a unit moved to a battlefield by a spell can become an attacker or defender, provided that the movement results in a combat showdown.

Whether the unit is considered an attacker or defender depends on the context of the battlefield and the combat:

1. If the movement triggers combat: If a spell moves a unit to a battlefield where it becomes an attacker or defender (for example, by moving an enemy unit into your occupied battlefield, or moving your unit into an enemy-occupied battlefield), that unit will gain the corresponding designation.
   • According to RiftJudge FAQ #5394, if you use a spell to move an enemy unit into your occupied battlefield, that enemy unit is treated as the attacker because it is the unit that applies the contested status to the battlefield.
2. Designation Timing: Units gain the attacker or defender designation during the Showdown Step (Rule 442.1.a). If a unit is moved to a battlefield during an ongoing combat, it will gain the attacker or defender designation during the cleanup phase following the action that caused it to become present (Rule 442.1.a.3.a and 442.1.a.4.a).
3. Combat Requirement: Attacker and defender designations only exist during combat. If a unit is moved to an empty battlefield, no combat occurs, and therefore no units are considered attackers or defenders (see RiftJudge FAQ #5513).

In summary, the unit's designation is determined by its role in the combat showdown, not by the fact that a spell was the source of the movement.