The phrase "doth in to" is an old-fashioned way of saying "does into" or "becomes part of". This phrase has largely been replaced with more modern alternatives, such as "merges into", "integrates with", or "joins with". These synonyms all convey the same meaning as "doth in to", and are more commonly used in modern language. When writing or speaking, it's important to use language that is clear and easily understood by your audience, which is why it's important to familiarize yourself with alternative phrases that can help you communicate your intended meaning more effectively and clearly.