It looks like this snippet is not at the right place, the output contains `<em>` tags since you are using `MD_CHAR_EMPHASIS`. You should define a `MD_CHAR_QUOTE` or something like this and **not** put this snippet under the following condition:

~~~c
if (md->cb.emphasis || md->cb.double_emphasis || md->cb.triple_emphasis)
~~~

Which is at line 2702. Just take a look at how the other extensions work (such as superscript). If you run into trouble, just ping me ; I would be glad to help you. :smiley: