Regularly ruin board game, introducing new complexity (8)

'complexity' is the definition.
The definition and answer can be both human attributes as well as being singular nouns.
Perhaps you can see an association between them that I don't see?

'regularly ruin board game introducing new' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'board game' becomes 'chess' (chess is a kind of board game).
'introducing' is an insertion indicator (some letters introduced or inserted into others).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
The alternate letters of 'ruin' are 'ri'.
'chess' placed around 'n' is 'chness'.
'ri'+'chness'='RICHNESS'

Can you help me to learn more?