This was answered in an FFG Sez: http://boardgamegeek...icial_FAQ#toc69
Q: In "The Dawnblade" and "The Desecrated Tomb," when the quest book says that a hero or Sir Alric is carrying the Dawnblade/Duskblade, is that character actually wielding the item and allowed to use the abilities associated with the relic? If this is the case, is Sir Alric allowed to have two relics in these quests? For example, could he begin the encounter with the Shield of Zorek's favor and then later pick up the Duskblade?
A: No, carrying the Dawn/Duskblade doesn't give you access to its Relic card abilities; it only functions as an item-objective within the confines of the quest. It also does not count toward Alric's relic limit.
In fact, aren't Lieutenants counted as master monsters according to the lieutenant packs?
This is only the case for the lieutenant when summoned during a quest in which they are not already present (usually by replacing master and possibly some minion) monsters from a group. The cards from the summoning are a bit more limited (they don't have attributes, and there may be other differences). You are not allowed to play these cards if the lieutenant is already present in the quest, as is the case above, so that rule doesn't apply. (You're still right in that they can't use it, but this isn't the reason.)