Blocking someone on Kik Messenger will not delete you from their contact list.
Messages from the blocked person will be hidden and all chats with this person will be deleted. Also, when the blocked person tries to send you a message, they don't know that they are blocked and their message is never delivered to you.
However, previous chats, your profile picture, as well as changes you make to it will still appear on the blocked person's app.
When a message is sent from you to another Kik user, the message exists on your device and their device separately. Once Kik servers have relayed the message, they delete it from their system. Blocking a user will not delete the messages that have already been delivered to them.
See the FAQ on managing messages from new people to learn how to use the New People feature.
Check out 10 tips for safe instant messaging, featured on Alibaba.com.