The use of relative pronouns kende 'who' and kual or kua 'which' is by and large restricted to formal contexts and/or educated speakers. These relative pronouns are not case-marked. In other words, no distinction exists between subject relatives and object relatives. Nevertheless, their pronominal status clearly seen in their ability to appear with the plural marker nan, and their ability to occur as object of a preposition (see Feature 94 "Instrument relative clauses" for the latter).
The more common, all-purpose relativizer ku has the status of complementizer. It does not admit plural marking, and where relativizing the object of P, it requires preposition-stranding.
Source: Muysken 1977: 86
Source: Kouwenberg 2007d: 317
Source: Maurer 1988a: 406
Source: Extra: 25 June 2009, p.6.
Source: Extra: 25 June 2006, p.6