The Sword of Seals can be found in the shrine of seals... when you get there (in FE7), you can see a sword (neat cameo)
Hartmut's sword, Exacuss is emperor's sword. Sometimes reffered as Conqueror's sword. Hartmut is most likely to be an emperor. A lot of stubborn headed members of Sanctuary of Strategy kept thinking that Hartmut was a hero and Roland was a cavalier...