Why are you doing this?
Existing languages at this level of abstraction and efficiency are unsatisfactory. In particular: Too little attention paid to safety. Poor concurrency support. Lack of practical affordances, too dogmatic about paradigm. What are some non-goals?
To employ any particularly cutting-edge technologies. Old, established techniques are better. To prize expressiveness, minimalism or elegance above other goals. These are desirable but subordinate goals. To cover the “systems language” part all the way down to “writing an OS kernel”.