Thanks for this! So, if ok with you [MENTION=552]Creamsteak[/MENTION], Thaliss would take the ritual caster feat, ans switch his book of ancient secrets warlock invocation to something more relevant (repelling blast or more likely, misty visions). The book of ancient secrets invocation allows to cast any ritual, but Thaliss will not continue progressing as a warlock, so it is kind of wasted since he'll never be able to use level 3+ rituals. By taking the ritual caster feat, Thaliss continues to be able to use rituals (he only know wizard rituals anyways), and gets to use something more useful in the warlocks arsenal.
OK?