Don't assume you know everything, there are a number of surprises coming in Londo's and G'Kar's arcs.
JMS doesn't mind showing you the ending, considers the "how" you got there at least as important as where you go
A Prequel TV Movie In the Beginning, contains some spoilers up through S4, but, he has often recommended it as a Starting point, instead of The Gathering
You've known for a long time that G'Kar kills Londo, this is why Londo has such an aggresive relationship with G'Kar, even over and above G'Kar being a Narn. Londo has always known, from the first time he saw G'Kar's face that G'Kar was the man of his dreams.
JMS doesn't mind showing you the ending, considers the "how" you got there at least as important as where you go
A Prequel TV Movie In the Beginning, contains some spoilers up through S4, but, he has often recommended it as a Starting point, instead of The Gathering
You've known for a long time that G'Kar kills Londo, this is why Londo has such an aggresive relationship with G'Kar, even over and above G'Kar being a Narn. Londo has always known, from the first time he saw G'Kar's face that G'Kar was the man of his dreams.