What are my visa options in Korea?

Hi,

My name is Marcel, I'm a German citizen living in London and would like to move to Korea in the future.

I know a company that would sponsor me if I make sure I'm eligible and know my options. 

On that note. I'm 23, have 5 years experience in Recruitment and work as Senior Manager. I however not hold a university degree. 

What options do I have for a work Visa?

I am also considering obtaining a D8 visa as last resort but have difficulties finding an exact amount of investment that has to be made in order to be eligible.

Could you please advise me on my options?

Thanks a lot!