“Voltanis the Adjudicator” can be Special Summoned by its effect immediately after your Counter Trap’s effects have resolved.
Tributing all your monsters to Special Summon “Voltanis the Adjudicator” is a cost. If you do not have at least 1 monster to Tribute, you cannot activate this effect.
“Voltanis’s” effect does not target the cards you want to destroy.
If “DNA Surgery” is on the field making all monsters Fairy-Type, then all the monsters you Tributed will count towards “Voltanis’s” effect for determining how many cards are destroyed by “Voltanis”.
You cannot Special Summon “Voltanis the Adjudicator” if “Mask of Restrict” is active on the field.