Is there any adjectives (phrases) to describe Mark?
Sure. There are many. Here are a few words you can use (but note that some of these are nouns).
- Hanger-on: If you describe someone as a hanger-on, you are critical of them because they are trying to be friendly with a richer or more important person, especially in order to gain an advantage for themselves. (Collins)
- Manipulative: A manipulative person tries to control people to their advantage. (Cambridge)
- Conniving: A conniving person deceives others for their own advantage. (Cambridge)
- Cunning: Someone who is cunning has the ability to achieve things in a clever way, often by deceiving other people. (Collins) Also see shrewd and unscrupulous.
- User: a person who uses a relationship with someone only in order to get some advantage for themselves. (Cambridge)
- Opportunist: If you describe someone as opportunist, you are critical of them because they take advantage of any situation in order to gain money or power, without considering whether their actions are right or wrong. (Collins)
- Self-seeking: interested in your own advantage in everything that you do. (Cambridge). Also self-serving.
- Leech: a person who gives attention to someone over a long period in order to get their money or support. (Cambridge) Also see parasite.
Basically, Mark's intention is to get that contract, as you say. He intends to manipulate this mayor to get what he wants by being his friend. I would say that for this case, the first five are quite appropriate.