About the only reason for using Excal over Almace is if you are in a situation where there is an Amnesia aura or it is beneficial to use Requiescate over CDC due to it's special properties (ignoring defense attributes similar to twilight scythe). And if you're going to offhand any relic, the best choice is Mandau due to the high base dmg and low delay. This is subject to if you think it is worth using over a str/att ToM sword though.