You place a Spell Counter on this card when the Spell Card resolves, so if "Magic Jammer" is used to negate the Spell Card's activation then you do not place a Spell Counter on this monster. But if "Imperial Order" is chained to the Spell Card, you still place a Spell Counter on this monster because the activation of the Spell Card was not negated. If the Spell Card was a Continuous, Equip, or Field Spell Card, and “Dust Tornado” is chained to its activation and destroys it before it resolves you still place a Spell Counter because the activation of the card was not negated.
If you activate a Spell Card, and your opponent chains "Call of the Haunted" to Special Summon "Skilled Dark Magician, "Skilled Dark Magician" does not get a Spell Counter for that Spell Card because "Skilled Dark Magician" must be face-up on the field when the Spell Card is activated and when it resolves in order to get a Spell Counter.
You place a Spell Counter for any Spell Card that is activated, including Equip Spell, Field Spell, etc.
When you use the effect of a Continuous Spell Card that is already face-up on the field, such as "Inspection", or sending "Wave-Motion Cannon" to the Graveyard, or paying for "Messenger of Peace", you do NOT place a Spell Counter on this monster.
When "Double Spell" is played, you get a Spell Counter on this monster for the activation of "Double Spell", but not for the target of "Double Spell" because the target is never activated; so you get 1 Spell Counter on this monster.
You do not place a Spell Counter on this monster when you attach or detach a Union Monster because that is not the activation of a Spell Card.
If you activate "Monster Reborn" or "Premature Burial" to revive this monster, this monster does not get a Spell Counter for "Monster Reborn" (it has to be face-up on the field before the activation of the Spell Card).
You can only Tribute this monster for its effect during Main Phase 1 or 2 of your turn.
This monster's effect does NOT target and you select the monster when you resolve the effect, so if you Tribute it to Special Summon "Dark Magician" from your Graveyard and your opponent chains "Disappear" and removes that "Dark Magician", you can Special Summon a different "Dark Magician" from your hand/Deck/Graveyard instead.
If there is no "Dark Magician" in your hand/Deck/Graveyard you can still activate this effect but your opponent can verify the contents to make certain, and then the effect disappears.
When "Skill Drain" is active, and you or your opponent activates a Spell Card, do not place Spell Counters on this monster. Any Spell Counters that are on this monster are removed when "Skill Drain" is activated.
If a player controls the opponent's "Skilled Dark Magician" and Tribute it with 3 Spell Counters, the player who controlled and Tributed the "Skilled Dark Magician" is the player who Special Summons "Dark Magician" from the hand, Deck, or Graveyard.