The dative case is added to nouns to mean "to", "for", or "for the sake of".
Again, remember that suffix rules for Thamil cases, as well as our basic set of suffix rules, should be used in conjunction with the dative case suffix, if they are applicable. In general, non-case-suffixes (-ஆ, -உம், etc.) only follow the basic set of suffix addition rules. Case suffixes (-ஐ, -க்கு/-உக்கு, etc.) are added by first using case suffix rules, if they apply, before using the basic suffix rules.
Only a handful of words, which are all pronouns, add the dative case slightly differently.