You can use the skill when your Life Points are 1000 or less. You do not have to spend Life Points to activate a card until your opponent's next turn ends. You can only use the skill once per Duel.
Life Cost 0 is the most recommended skill viable for a specific deck like Ultimate Cyber-Stein. However, this skill might never get on top of the tier. A very unique skill in current skill pool of duel links’s.
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