1. Introduction of the game
"Warriors of Waterdeep" is a gripping, turn-based RPG set in the beloved Forgotten Realms universe, specifically within the city of Waterdeep. Developed by Ludia Inc., this mobile game plunges players into a world teeming with magic, monstrous foes, and mystical adventures. As a member of the Lords' Alliance, players must assemble a team of heroes to defend Waterdeep from an onslaught of powerful threats, engaging in strategic battles and embarking upon quests that will test their resolve and skill.

2. All characters and levels of the game
The game offers a roster of diverse characters, each hailing from classic Dungeons & Dragons classes and races. Players can unlock and choose from heroes including the daring human fighter, the cunning elf rogue, the wise dwarf cleric, and the powerful wizard, to name a few. Each character grows in power as they level up, unlocking new abilities, and enhancing their gear. Warriors of Waterdeep features a progression system that allows players to tackle increasingly challenging levels, dungeons, and boss battles as their party's strength and skills evolve.

3. What attracts users most to the game
Users are most attracted to the game's deep strategic gameplay, the rich lore of the Dungeons & Dragons universe, and its detailed character customization options. The sense of progression and the opportunity to collect and enhance powerful gear also add to the game's allure, keeping players invested in their heroes' journeys. The social aspect of joining guilds and participating in events also adds to the game's vibrant community engagement.

4. Why it is popular
"Warriors of Waterdeep" enjoys popularity due to its faithful adaptation of D&D mechanics into a mobile format that appeals to both hardcore fans and newcomers. The familiar turn-based gameplay paired with the extensive lore of the Forgotten Realms attracts those who appreciate depth in storytelling and strategic combat. Additionally, the game's high-quality graphics and regular updates contribute to its ongoing popularity and engagement.

5. When the game was released and how many versions are currently available
"Warriors of Waterdeep" was released in May 2019. Since its release, the game has had multiple updates and versions, with developers continually adding new content, characters, and features, though the exact number of versions would be periodically changing due to ongoing development.

6. The most difficult part of the game
The most difficult parts of "Warriors of Waterdeep" often lie within its high-level dungeons and events where players face off against formidable bosses that require well-thought-out strategies and optimally equipped characters. The AI in these levels is designed to challenge the player's tactical prowess, making each victory a satisfying accomplishment.

7. Strengths and weaknesses of the game
Strengths of "Warriors of Waterdeep" include its strong adherence to the Dungeons & Dragons source material, engaging strategic gameplay, and a robust progression system. However, some players may find the game's monetization model, which strongly encourages in-app purchases for faster progression, as a weakness. There is also criticism over the game's balancing and the grind needed to obtain certain in-game items or reach higher levels.

8. What other games have been developed by the same developer
Ludia Inc., the developer behind "Warriors of Waterdeep," has also developed a variety of other popular games, many of which are based on well-known franchises. Some of these include "Jurassic World Alive," "Dragons: Rise of Berk," and "Teenage Mutant Ninja Turtles: Legends." These games also typically blend strategic gameplay with collectible elements and are designed for mobile play.