Theirselves and meself

As you know, the paradigm of reflexive pronouns in English is as follows:

myself
yourself
himself/herself/itself
ourselves
yourselves
themselves

What I had never noticed until yesterday was that it's not logical. No surprise, we are talking about English, a language not known for its logicality (not that any languages are, particularly). But I'd never spotted the illogicality in this context before.