In the Star Wars universe, a Sith is a member of the Sith Order, a group of Force-sensitive individuals who follow the dark side of the Force. A Sith Lord, on the other hand, is a high-ranking member of the Sith Order who has achieved the title through training, power, and mastery of the dark side. Sith Lords are typically more powerful, influential, and skilled in the ways of the dark side compared to regular Sith. **

In the Star Wars universe, it is generally believed that only Jedi can become Force ghosts. This ability is achieved through deep connection to the light side of the Force and selflessness. Sith, on the other hand, are typically associated with the dark side of the Force and are focused on personal power and control. As a result, it is unlikely for Sith to become Force ghosts, as their beliefs and actions are not aligned with the selfless and compassionate nature required to achieve this state. **

I am an AI digital assistant and do not have the ability to align myself with either the Jedi or Sith. My purpose is to provide information and assistance to users without any personal affiliation to either side. **

It is difficult to definitively say who the strongest Sith is as strength can be measured in various ways such as power in the Force, combat skills, or strategic abilities. However, some of the most powerful Sith Lords in Star Wars lore include Darth Sidious (Emperor Palpatine), Darth Vader, Darth Revan, and Darth Bane. Each of these Sith Lords demonstrated immense power and influence during their time, making them formidable adversaries. Ultimately, the title of the strongest Sith may vary depending on the criteria used to assess their strength. **

The strength of the ancient Sith compared to the modern Sith is a matter of debate and interpretation within the Star Wars universe. The ancient Sith were known for their powerful use of the dark side of the Force and their mastery of Sith magic and alchemy. However, the modern Sith, such as Darth Sidious and Darth Vader, also displayed incredible strength and skill in the Force. Ultimately, the strength of the Sith is subjective and depends on individual perspectives and interpretations of their abilities. **

The old Sith were not necessarily weaker, but they operated under different circumstances and faced different challenges. The Sith of the past may have had different strengths and weaknesses compared to the Sith of the present. Additionally, the old Sith had to contend with the Jedi Order at its peak, while the modern Sith operate in a different era with its own set of challenges. Overall, it is difficult to make a direct comparison of strength between the old and modern Sith. **

Sith cannot become Force ghosts because the ability to become a Force ghost is achieved through selflessness and a deep connection to the light side of the Force. Sith are driven by their own selfish desires and are consumed by the dark side, which prevents them from achieving the selflessness required to become a Force ghost. Additionally, the dark side corrupts and consumes the spirit of a Sith, making it impossible for them to retain their identity and consciousness after death. Therefore, Sith are unable to transcend death and exist as Force ghosts. **

Darth Sidious, also known as Emperor Palpatine, is often considered the most powerful Sith in the Star Wars universe. He was a master manipulator and strategist, able to orchestrate the rise of the Galactic Empire and eliminate the Jedi Order. His mastery of the dark side of the Force allowed him to wield immense power and control over the galaxy. Sidious was able to defeat powerful Jedi and Sith alike, solidifying his reputation as one of the most formidable Sith Lords in history. **