Welcome to Ravnica
The Guild credit system has been simplified. Convert all guild credit into gold pieces. Each additional renown gained with a guild yields 100gp. Your ability to purchase magic items is based on guild renown.
Common: 1 renown
Uncommon: 3 renown
Rare: 10 renown
Very Rare: 20 renown
Legendary: 50 renown
Renown is not necessary to purchase non magical items, however, it could be useful in negotiating terms. (Free Delivery or expedited crafting at 5. 5% price reduction at 10. 10% price reduction at 20.)
Alternate PC rules have been amended. You may create a maximum of three characters throughout the course of the campaign. There are no guild or color restrictions. Your first character must reach level 5 before a second active character can be created. You must have one character at level 10+ and one character at level 5+ to create a third active character. Waive these restrictions if you don’t have any active characters (most likely due to character death). Non active (eg deceased) characters still count towards the limit of 3 total characters that may be created per player. Spend their lives wisely.
When a DM spends DM XP to gain a level the character also gains renown equal to the proficiency bonus at the new level. This bonus does not apply unless at least half of the total XP required to gain this level was spent using DM XP. At least 1 of this renown should be spent with the character’s home guild.