Melhay
Is Adonalsium going to be mentioned by name in Warbreaker and The Way of Kings or is he going to be an underlining "God"(I don't know what to call him yet) idea? I am curious now, so I will have to keep my eyes open for him.
Brandon Sanderson
Adonalsium (Ahy-doe-Nahl-see-um) will be mentioned by name again. Ruin and Preservation were what have been called Shards of Adonalsium. (The Voice from Warbreaker is another Shard.)
Melhay
Is this "character" a common link between your books for religion or magical or maybe even both?
Brandon Sanderson
Adonalsium has to do with the Cosmere, which is the word Realmatic philosophers use to refer to the greater universe of the Shardworlds. It's hard to separate religion, magic, science, and society in most of these worlds. So "both" is a good guess.
Melhay
I was curious because he just seemed to appear and nothing further on him/it. Thank you for mentioning that he is in these two other books, I will have to look for hints of him.
Brandon Sanderson
The word Adonalsium (or, well, the miss-spelling of it) appears in only one of the books. Other clues and links between the books can be found as well. (Some people on my forums have spotted some of them. Others have gone unspotted so far.)