How to Render a Liquid Templates in an Email Template
In order to render a liquid template in an email template you will need to first create your liquid template. The Email template merger will set the scope of your template to be the target object.
Liquid Template Merge Tag
In your Email Template add the folllowing merge tag to merge a liquid template, replacing 'TEMPLATENAME' with the name of your template.
{{LiquidTemplate|TEMPLATENAME}}
Limitations
Currently Liquid template merging is not supported for Campaings.