When Surrakar Spellblade’s second ability resolves, you either draw a card for each charge counter on it or you draw no cards at all.

If Surrakar Spellblade leaves the battlefield after its second ability triggers but before it resolves, its last existence on the battlefield is checked to determine how many charge counters were on it.

If you cast an instant or sorcery spell, Surrakar Spellblade’s first ability triggers and goes on the stack on top of it. The ability will resolve before the spell does.