Karuna Reiki is developed by William Rand and is very popular today. It was introduced in 1995 but is used by many now-a-days. Karuna Reiki, itself, has many levels/sub levels, but for that, too, you should be Master in “Reiki” before you go for any other Avataar of Reiki.
Karuna is a Sanskrit Word and it means Compassion/Love.
Here, is an interview with William Rand himself.
“For Reiki Therapy and Alternative Medicine Counselling, contact me on email@example.com. Wishing you a Healthy life forever.”