'Decentralized Finance (DeFi) via Blockchain. Civil and Regulatory Principles': Decentralized Finance (DeFi) is the hub of the Web3. The pursue of complete decentralization is currently not convincing in every respect. Problems with regard to enforceable liability claims and tangible liability subjects have hardly been considered to date. The global involvement of regulatory authorities with the construction of possible addressees of supervisory regulations also shows the existing need for clarification. The thesis is dedicated to these specific problems. In addition to the development of a regulatory concept under supervisory law, civil law problems are mainly solved using the existing legal basis.