Krul is the creation of Delano Cuzzucoli, who wanted to see if he could construct an entire alphabet using a single symbol (in this case, a "curl") which would be combined with flipping and adding dots and lines to produce a wide variety of possible letter forms. It is inspired somewhat by the "bow" and "stem" method used in Tolkien's Tengwar.
Krul is used to write English, but can also be used in other Latin-Alphabet languages and Delano is going to use a modified version of it in one of his own constructed languages. The word "krul" is Afrikaans and means "curl".
If you need to type in many different languages, the Q International Keyboard can help. It enables you to type almost any language that uses the Latin, Cyrillic or Greek alphabets, and is free.