The first sentence obviously refers a previous one. Literally it means "In X century it was commonly used to designate Scandinavians who were élite of the ancient state". You can't understand what is meant by "IT" without having read the previous sentence. In your sentence, the demonstrative pronoun (ОН или ОНО) is used in the instrumental case in accordance with the requirement imposed by the following verb: "ИМ называли", it's like "этим именем называли". Пишут им, карандашом. Называют им, именем. The second phrase is not in correct Russian. It really may be understood as "facts from a shadow", but does not sound natural at all, this "тенька" can hardly be derived from "тень". It sounds wrenched and tasteless. May be it's not Russian but rather some of other Slavic languages.

2. In rubrinka show (facts from тенька): тенька can means the river Tенька or shadow "тень" and "ка" is suffix.

Понятно :) Но я не понимаю что это переводится на английский :(

"в эфире рубринка ((факты из тенька))" - это не литературная норма, но такой стиль часто используют в эфирах/каналах ютюба, ориентированных на молодёжную аудиторию

Thank you for your quick answer!! I couldn't think that "им" is an instrumental form of "оно"! At first I didn't have no idea what you are saying, but I know thank you :)