Ignis is a child chain of the Ardor blockchain. Ardor is a scalable blockchain platform. The parent ardor blockchain guarantees the security of all its child chains. It tries to execute the blockchain as a service concept. You only need to have a good parent chain. All child chains get features, enhancements and upgrades of the main parent blockchain. Proof of stake (where users lock their coins for annual interest) is used to secure the system. This is energy efficient as the alternative would be to use a proof of work system where lots of electricity is wasted on useless calculations.